Indeed, It was their first product, it was primarily written by Bruce Borden (of Rand Ports fame) and Greg Shaw- and I was the first customer for same @ Tektronix [we debugged it and our own against Stan and my VMS implementation]. Steve Glaser wrote a HyperChannel driver for it, which is a pretty amazing piece of work. BTW: Somewhere, I have the mailing envelope that is dated the "32 of December, 1980" because they had an end of the year clause with their VC's and ran into a problem right before they shipped it too me. I thought that was pretty cool, so I kept it.
As for if I have contents of the UNET tape -- i.e. the bits themselves... the answer is maybe. I'm not sure to be honest. The original tape would have been at Tek but I did have somethings in my archives from those days, i.e. my home directory which in couple of cases has compressed tar or cpio images of interesting things. For instance it was discovered a few years back that I last known copy of UCDS - which Dennis was able to get released as a very late delivery of part of V7 and Warren now has in his archives.
The point is, I do have a box of tapes from those days in my basement that I have not tried to read in a few years - so assuming I can read them (which is a huge) if although we did succeed as with UCSD and I have the information you are looking for ... the status/ownership of the bits is 3Com's -- which makes it sticky. It's there copy-written IP.
We would need to find someone at 3Com to release it. Borden might be able to help as the original author, but he has not worked for 3Com for eons, plus I have not talked to him a few years, although I may know how to find him. Bob Metcalfe might also be able to help, but other than being a stock holder, I'm not sure what influence he has with 3Com management. Similarly, I have not spoken to Bob is while either, in fact the last time I did he was still a Principal at Polaris and one our Board of Directors at Ammasso -- I think he's now @ UT Austin.
Clem