Just finishing restoring my 240z quarter windows but was wondering if sealant is required in the groove where the glass sits, i thought i read somewhere that the FSM says its not required?

It is always better to apply sealant there.

Thanks Blue, done today, got a bit messy though!

Yeah it is tough putting it together with the sealant however you can remove the excess sealant when it starts to tack.

With no sealant, water will weep in..... especially on the bottom edge of any glass seal where it pools.