Copper head gaskets for Kohler M18?

I have been looking for copper head gaskets for my kohler, but all I've been able to find are ones that fit 16hp. Are the 16 and 18 the same part?

I just got one from copper gaskets unlimited of AZ for a Kohler cv490s.  You can email them with your engine model and spec number along with any details such as the stock gasket number and a picture.  If they don't already have it in their computer they might ask you to send them the old gasket to use as a template.  I spoke to Lani but this site won't let me post links as I'm new.  Just do a google search for them and you will find their site.  If they already have the pattern in their system they can cut it and have it to you in just a few days.  It took them 3 days to get it to me cross country.  I hope this helps you out.