The serial connector doesn't look like it was plugged in for a long time - it's just the type of shell used. It looks that way because it starts flaring out from flat to accommodate the shell. However, I would say it was used. There's a small possibility the bubbling is a defect from manufacturing, but the black marks are not. However, any use was likely fairly light - there's not much shine going on with it.
You can use a standard DIN5->PS/2 adapter with these no problem at all. The Alps Glidepoint will be a real problem though. 
Thanks for the info! I agree it doesn't look like heavy use, however any use makes it not new, and not worth the $200.00. Bob at Northgate Repair says he can send me a USB adapter that will work with the glidepoint.
Sorry for the kind of off topic - But why's that?
(What's wrong with disputes?)
I guess I'll rephrase. I'd rather work something out with the seller first in respect to a refund as opposed to issuing a dispute with eBay and Paypal (which can take a while and isn't foolproof). I will if the seller won't work with me.
Here's the message I sent, FWIW:
Dear Seller,
I received the Omnikey Keyboard today in the mail. I wanted to connect with you first regarding a few things:
1) Unfortunately I can't (at least not immediately) use the keyboard. It's not a PS/2 keyboard as advertised. It's an older AT model. I can contact some people to see if a normal adapter works on the Omnikeys.
2) I was hoping, that it was advertised as brand new, there would be paperwork (a manual) to accompany the keyboard, as I thought it had programmable features.
3) The keyboard is in good condition, but likely not brand new.
This leaves me in a place where I know I paid a very premium price for this keyboard. One year ago they were selling for around $75-100 brand new. I'd rather not go through the hassle of returning it to you for a full refund. I'd like to reach a compromise about a partial refund given the condition. Please let me know as soon as possible (by Sunday) if that will be workable. We can figure out what is agreeable.
Thanks for your time.
Truly,
Crazeco