Do you know if it's a fully hackable PSP?
If you don't update to 6.20 OFW, run the 6.20 LCFW and then use PSPIdent to identify it. If it's not fully flashable you stay at 6.20 and then it's up to you whether to want to permanently install the PRO B10 firmware or leave it as a run from XMB thing.(slight impact on boot speed every time vs. launching CFW each time you want it)
If it is fully flashable (as revealed by PSPIdent) then you update to 6.60 and use 6.60 PRO-B10 and perm install it with a cIPL flash. (doesn't impact boot)
All this is in the sticky by Rydian...