Literally impossible to tell without lab analysis. The only RC benz I’ve fucked with that take unusually long to kick in is flualprazolam and they don’t take 4, more like 2-3 hours - for me at least. And once they do no matter how low a dose is, it’s lights out shortly after. Not in a blackout sort of way, but in an extremely muscle relaxant, slightly euphoric then straight to sleep way. No matter what I’m doing, if I feel it kicking in and don’t immediately hop into bed I’m falling asleep no matter where I am.
Could be clobro, I’ve heard that takes forever to kick in but personally wouldn’t know and don’t want to say that’s what it is. I’d suggest not buying bars off the street if they can’t tell you what it is, or at all really. I purposely bought the flu-alp bars I have for when I get overstimmed or just know I need to sleep and not going to be able to without assistance, as they work damn fine for it. But they were advertised as what they are, not just some mystery bar.
‘Busses’ or R039s are some of the most commonly pressed bars and could have anything. Same with b707s and s903s aka ‘hulks’. Same with GG249 and X2s. Pretty much all US branded bars, tbh, if not known to come directly from the pharmacy are most likely a press of literally ANYTHING. Only way to know what’s in them is buying directly from the source that knows what’s they’re pressed with, but even that is sketchy and often not correct. Lab analysis is the only real way to know