Nikon d600 body good for wedding photography?

I have a 18 200 5.6 lens now and a sb 700 flash and around 2000 $ to invest for a body I be working mostly weddings should I buy the d600 r buy a cheaper not full frame body and invest in a nice glass? Opinions?

18-200 f/5.6 no use for weddings. Will that even work on a full frame body?

Invest in lenses!

Invest in some better lenses.

The 18-200 is designed for aps sized sensors and not full frame. While it is a fine walk around lens, it is not suitable for wedding work by a paid shooter. And if you are asking this, then you are not ready to shoot weddings either. You need fast lenses, at least one more flash, two bodies, and lots of know-how.