Not for the main boards no, it might get added as a category extension if someone is serious about running it. Running it on a modern pc requires ini editing or a 3rd party program as well, so becomes a minefield for verification.
Yeah.. I kinda wanna run Sonic 3 & K but the problem is i have a really old PC (2007 Windows) and Sonic and Knuckles collection is really the only version my PC can run soooooo
To be honest, with a PC from 2007 you're likely to run into not being able to record the gameplay effectively either, and probably having a phone/camera pointed at the screen for upwards of 90 minutes for a full run will likely give you other issues too.
As of today, any new submissions of S3K from the Steam version will no longer be allowed. This is due to a couple of factors but mostly being inhibited availability as SEGA delisted it when releasing Origins. Any existing runs will remain unaffected.