I get some hard callouses if I play a in a relatively short amount of time, but lately it's been that my fingers are just getting "thicker"
The only places I get truly hard peices of skin is exactly where I hit the string. I've been playing long enough that my technique for fingerstyle is hitting the same spot every time, so I will get a blister there, then leave it for a while, then play again and get a blister. Repeat for a week or two and then I had a blister. This is especially true for pop and slapping.
As of late though, now that I no longer live in dry Las Vegas, and I'm in a more humid environment, my fingers are just a little bit thicker. They still peal a lot, and it looks like I've torn up my fingers, but they don't hurt. Back in Vegas I would get callouces that were my entire fingertips, here I don't get that.
An interesting trick I found about a few years ago to give yourself an artificial callouces is superglue. It literally gives you a plastic coating over your fingers. I prefer to do a couple coats on my fingering hand, a one or two coats on my fretting hand. The last time I did this (2 weeks ago) I just put some one my fretting hand, a single coat or two, and then left it. Now my fingers are generally thicker. After a couple of days the superglue almost became one with my fingertips.
I don't suggest doing the superglue trick unless you need it. The only time I ever resort to that is when I'm jamming and get a fat blister, or I have a reason to play for a lot longer than my fingers can handle, like learning 10 chili peppers songs in a week. ><
If you can already play 2-3 hours and your just starting..... kudos man. It took me months to build up to that.
Also, callouses don't really matter. The reality is that you are going to play through an amp at the show, and you are going to want to play softer, and let the amp do the work. Same goes for popping and slapping. I know its hard to soften up, but turn your music down, and play don't play your bass as hard.