Well if it leaks you need to replace it so it doesn't matter which one you have, I think you can only get the newer one now. And yes that's where the gasket goes. Thomaspin's web site will be very helpful also but it is an easy job.

__________________
1985 300D Turbo ~225k
2000 F350 (Powerstroke) 4X4, SWB, CC, SRW, 6spd ~148k
1999 International 4900, DT466e (250hp/660 ft/lbs), Allison MD3060 ~73k