This board is from a CNC PLC. As you will see in the images, these 3 boards stack and are connected by gold pins. The reason why I think it could be a HGTC+ is the quality of all 3 boards and if you look closely you will see there is gold edges on the boards. The gold edging is a bit hard to see on some of these boards from them just being old and tarnished a tad.
I have some more I will be sending in with my next shipment, but in my previous shipment which had some of these boards, they were only graded as HGTC. I think a part of what is confusing me is Sharkscrapper made a video about grading telecom boards and mentioned that some telecom boards will be upgraded to "HGTC+" AKA gold edge, gold cap, and CNC boards if they have really good components that "push them up into thst catagory" as he explained it.
Thank you for any information, this has all been a very fun learning process for me.

Sold all connected together or separately?

I could see the smaller middle board bringing down the whole thing connected. The other two boards definitely clear high Telco on their own but I'm not sure where the line is for jumping to cnc/gold edge boards. So maybe they can't on their own or maybe as a whole the middle board prevented it.

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Here to learn more so I can recycle more
My grades are my own opinion and not an official grade from Boardsort

1 - 3, will definitely be High Tel and the middle board I would throw in High Per.

What I can see why they don't make CNC/Gold edge is because the edging or masking needs more, and thicker; also most upgrades from High Tel to CNC/ Gold edge, at least one of the chips will be a gold capped IC or have heavy, heavy masking and layering on the board or inside the actually make of bread board/sandwich board. Usually has an older or thicker style of Gold fingers on them as well. The style of Gold finger shown here is the lower quality of the gold fingers types. Another I can see is, the IC chips are plastic, not ceramic; could make a difference on the era of and precious metals make up of each component. % or what not.

I sell it as a stack as I tend to think of it as a single board, just stacked vertically. That's a good point you brought up! I think emailing Chris will be the best solution to this. It's a strange category to begin with.
For example "gold edge, gold capped, and cnc board". Is it all 3, or does just one of those things help "push" it into that catagory. Sharks scrappers video on telecom boards really confused me because on my previous order, I had a few boards that looked like they should be that grade but weren't.
There are two images of "HGTC+" that cone to mind from Boardsort.com itself. I believe one is from the video on youtube where the board is edged in gold, then there is the one in the "e-scrap pricing" pages that looks nearly identical to quite a few of my very nice HGTC boards I sent in but didn't get graded. Maybe the information on Shark's video is now obsolete due to market changes?
I will attatch the images from Boardsort.com that I am talking about.

Ask around though always. Say being a Telecommunication board or labeled a CNC PCB doesn't always determine that's the class by name but sometimes it does no matter what. It's back to experience just knowing and seeing different circumstances.

With my expertise, that gold edge board made it from that heavy masking plus the specific connector ends on the boards, RF mounts, are highly plated in gold; same as the little push pins on Wi-Fi cards. It's also probably inside the board as a layer too. Multiple gold BGAs, RAM, and looks like DLPs too.

The board similar to yours, why that made it; it has 4 rows of gold fingers, gold cap ceramic IC(8086) , and much more ceramic and plastic ICs.

Definitely separate stacking boards , riser pinned or padded boards separately. That could of been a deciding factor in grading.

Hopefully that gives you some insight at what to point out or keep a look out for when grading your boards and figuring what classes where.

If you can't determine it, you already know where to go, the forum.

Thanks a ton Spence, your comments were very informative!