I would clean everything, I believe BMX Euro BB's are all the same. I know in the road bike world there are different thread pitch's.
If you follow Profile's instalation guide you even put ptfe tape around the threads.
Taken from Profile website, Video no longer there
Installing a Euro (English/ISO) BB is pretty simple.You will need a 36mm headset wrench. Ideally, you should clean the threads of the frame, and then give them a light coating of grease. If you really want to do it right, because you hate hearing your BB creaking, then you should get some teflon tape from the hardware store and wrap the threads of the cups.
The drive side cup has a line around it and is left-hand (reverse) threaded. Carefully thread this cup into place. Insert the proper tube spacer for the width of your BB shell.
The non-drive side cup is right-hand threaded, so it tightens normally. Again, wrap the threads with teflon tape if you like, and snug it up.
When the cup is almost tight, it’s not unusual for the bearings to move outwards slightly- don’t freak out here. It’s better to have a tube spacer that’s 1mm too long than it is to have one that’s too short- you might as well not have one there at all in that case, and you need a tube spacer so that the bearings don’t pinch when the cranks are tightened down.
