No, they are separate things. And if the card can be either one separately, then they should be listed separately.
We don't list cards as AUSN500 because it's autographed and serial numbered numbered to 500 and use AUSN250 for the 250 version. So why would we do that with this? We list them as AU, SN500 and AU, SN250 and then the glossary gets populated with 3 entries, which can be used all over since there are many AU cards that are not SNed and plenty of serial numbered cards that were not signed.
Again, look at the 1973 Topps set - now the TCs are an "insert" set - but there is an example of cards that were TC and cards that are CL - then look at say the 1979 Topps baseball set. Those have the team picture on the front and the checklist on the back - TC, CL.
-- Dan --
Note: Please see my profile for more info regarding trading (section updated 3/4/2024). I have added a large portion of my inventory to the site, and currently have trading turned on (details are in my profile).