Need help ID'ing CNC head
 

I'm trying to ID some CNC heads that a local machine shop has (they are clearing out a bunch of parts they have laying around). The shop guy doesn't know much about them. He said his son bought them years ago from a Chevy parts counter in Chicago for his camaro & thought they were GM CNC heads. What he described doesn't sound right for them to be GM CNC heads. Numbers he gave me over the phone are 853, CNC 2042, 8312F7442856, there is also a 17 digit lasered number that he didn't read off, but I'm assuming is a VIN. The heads aren't carrying the yellow springs (unknown springs) & aren't 243 heads. I thought those were the only GM CNC ported heads. Price is around $600 for the pair. They are unused. This will be going on a budget NA LS1 rebuild. The CNC 2042 is what I was curious. Anyone familiar with which CNC company uses similar part numbers on the ends of their heads? Maybe that sells to Chicago dealers. Only thing I could find on google was a Patriot Performance Stage 2, but that was for an Ecotech motor. Thanks guys.
I have a set of 241 heads (from the archives they are slightly better than these 853 heads), but was thinking on these since just getting a multiangle valve job on these heads is around $400.

I might research Scoogin Dickey I could see dealers reselling their stuff.

If it were me and they are ported and unused, nice. I would offer him $500 or go with a ls6 ls2 head. JMO. Have him check the spring pressure.

Ended up getting them for $500. Shop got them in trade from a guy that thought his heads were bad. Bought these & found out his block was bad. Gave these to the shop in partial trade for the machine work they did. They checked the springs in front of me. 130 lbs @ 175 open & 360 lbs @ 125. Looks like they've never been used. Chambers have never been touched. Shop decked them 3 thousandths to clean them up. They pulled them apart for me. Seats were perfect & the guides were great. They were told he got them from a Chevy dealer in Chicago.