Series 70 Questions

I posed these questions at the end of another thread, but no responses - so new thread:

I recently purchased a like new Colt Series 70 45 ACP, S/N 70B07XXX, brought it home and field stripped it, and found it clean and proper inside. Haven't shot it yet. I did a Series 70 search on this forum and found this submission by chevis.

Quote:
I'd stay away from them both,series 70 don't mean nothing but trouble in the late productions...one rule of thumb I go by is the serial number.If it has a G in it it's GOOD.If it has a B in it it is BAD.The early models were good guns though,when quailty control was a whole better. Unquote

If chevis is reading this, it would be helpful if he would substantiate his comment, or if anyone else can comment pro or con I'd appreciate it. Can someone determine if my piece is "early" or "late" production. Should I be worried about the performance and reliability of my new purchase?

Thanks,