I just picked up a P229 DAK today.  It has a one piece grip that just snaps on from around the back strap.  I'm not
new to Sigs and this is the first time I've seen that the grips aren't screwed on.  Is this how Sig is doing things
now?  They don't seem very secure and rattle a bit.

Your 229 has the new E2 grips on it. SIG started making thier 226's and 229's with these grips and they are slimmer than the regular left anf right side grip panels that you are used to seeing onthier guns. I am planning on swapping out my grips on my 226 and 229 to thses new E2 grips as they are slimmer and narrow down the grip of the guns for people like me with small hands. I am pretty sure that you can always take the E2 grips off and put on regular grip panels if you wanted to go back to using those instead.

I have the Hogue checkered G10 grips on my 226 DAK.  They are even narrower than the E2 grips and omit the decocker lever cutout.  They are expensive though.

Yeah those are nice but like said expensive. I was just explaining to him what type of grips those were that came with his new gun.