Yeah, no worries about baseband. Pakistan has firmware G530HXC pda/baseband, so has Russia. XC is region code. XC, XX, XE, ZT, DV etc pda/baseband are all tested by me.
Csc difference usually cause some bloat at most, which can be removed when without root.
I have tried even worse with my phone and they never caused any signals issue, except for one Indian rom with INS or INU code in which i didn't receive messages. I am now on ZT region firmware on my phone with LTE option factory unlocked.