i ran a seach first before asking, but came up empty.  will tapco's "fal" saw style stock fit a century imbel L1A1? i've read that some external parts fit both inch and metric, but some require fitting or machining etc etc. seems like one big jumbled mess.

i've also read that minor trigger assembly repair is required to put another stock on the CAIs since they fooled around with it to get their thumhole stocks on. is this true?

No, probably not. If you truely have a L1A1 lower then it will NOT work. The easiest way to tell is to note the rear of the reciever/front of the stock. If yours is straight from top to bottom then you have a metric lower and the SAW stock will work.  If yours has "ears" that come out on the bottom edge of the reciever then it's an inch reciever and it WILL NOT work.

The handguards are interchangable between inch and metric.  The pistol grips and stocks are not. Just as an FYI, the SAW stocks are developing a reputation as a cheek bruiser.

As far as replacing the thumbhole stock, the grip bushing usually needs to be replaced as they were usually mangled or removed. The good news is that it's a cheap and easy fix. Check Gunpartsguy or Gunthings for the bushing. The trigger assembly is unaffected.

HTH,
Mike