Yes, there are casting numbers on the block. However, it is only a casting number and technically does not indicate what the block was machined to. But it's usually a very good indicator.
The casting number on the block will take the form
RF-XXXX-6015-XX
RF stands for Rough Finish (i.e. a casting)
XXXX is the prefix
6015 is the base number for all block castings. 6010 is the base number for a block that has been machined.
XX is the suffix (revision level)
After some searching, I have the following info for you. I've listed the major revisions to the block that you shold be concerned about.
1995-1998 3.0L - Prefix will be F5DE
1999 3.0L - XW4E-6015-AE or XW4E-6015-AG - Extra transmission bolt hole added. Extra oil feed added to RH side for Jag Cylinder Head VCT.
2000-2002 3.0L - XW4E-6015-BA - Change to small, 8mm knock sensor hole. Casting number moved.
The above should be true 95% of the time. Sometimes things update ahead of time. So a late '98 engine might have a 1999 block. Or a late '99 engine could have the '00 casting number but a large knock sensor hole. That goes back to the casting number not directly correlating to the finish machined part. They're not going to throw away perfectly useable castings because the number isn't right for tommorrow's new model year launch.
Location:
1995-1999: You find the casting number on the RH side of the engine (oil filter is LH) at the rear directly above the large 3/4" pipe plug.
2000+: Casting number moved to just behind the RH head deck. So it's not on the top or the side. Probably hard to view with the engine in the car and the head gasket sticking out.
Hope this helps,
Procyon
wow! Thanks!