Well, I've heard of this MIM parts...specifically I think in Springfield and Kimber, does my 80's series Colt Commader use these MIM parts?

How do I tell?

I can't remember what parts, other than the sear, are MIM in Colts, but they are not an issue.  As a matter of fact, I prefer the Colt MIM sear to several name aftr market sears.  I haven't seen the breakage issues with Colts at all.

What vintage is it?

I'm with Hobbes, no problems seen with Colt MIM sears.  Or Kimber MIM sears, for that matter.

The Colt mag catches I've seen as of late are MIM.  Saw one break.  

I don't mind a MIM grip safety, but replace everything else.

Of course not buying a gun with a ton of MIM parts in it helps.  Which is another reason I prefer Colt and Baer (no MIM parts in Baer and Rock River)

How to tell?

Disassemble the pistol, totally if you know how.

Take the slide stop for example.  On a MIM slide stop, you'll see from 1 to 3 small circular marks of raised metal about 1/8" diameter.  These are from the molding process.

On a cast part you'll see a thin line of raised metal.

A forged part will have a thicker line of raised metal.

Go through all the small parts on the gun and see what you find.  

The 4 MIM pieces in your pistol will be trouble free. The new ones have only 3 bits of MIM in them. I have many,  MANY thousands of rounds thru my series 80s with nary a problem with any parts breakage. The only problem that I was aware of was they used a MIM extractor for a short time until the complaints forced them to revert to a "real" one. I don't mind MIM for a low stress part, my problem is when it is used where it should not. I don't like the MIM sears myself but I will say that I don't see any problems crop up with them either.

It's a Colt Commander XSE model
Specific model is 04860XSE

Next time I take her apart completely for cleaning I will check it out.
Thanks