So, I was fooling around with my SA 1911A1 Parkerized Milspec last night, and found a little of a problem.  

None of my magazines would drop free!  UGH!!  They dropped free in a stainless 1911, so I know it's not the mags.

By my figuring, it's the parkerizing inside the magwell giving a little friction.  

My question... Should I take off the grips and try to polish the inside of the magwell a little??  I intend to use this pistol in IDPA and as backup in Carbine matches, so dropping mags free is very desireable.

I wouldn't reccomend polishing anything but the magazines.

The inside of your mag well could start to rust and what is worth more? the gun or the magazines?

but I know the magazines are not the problem.  Sure, they're cheaper.  Had a suggestion from the 1911 forums to check the grip screw bushings, so I'll check those.  I agree, I'd rather not have to polish off the parkerizing in the magwell, as it would then be prone to rust.  Maybe if I polish it, then blue it inside?  Probably won't offer much protection...

Funny thing, mine too.
Pull out the mag catch and you will find it to be .010wider front to back where the mag passes by it than others you may have.
This is out of spec and most any replacement will likely be worse unless you get a 'real' one from a colt or ed brown. Never mind ANY of the current crop of aftermarket mim parts to rectify your problem.
You can take a file to the 'face' of your catch and dress it down if you are handy at this. Do not modify the frame'well'. You will see the problem just by inserting a mag with the mag catch removed.
Btw, some mags are slightly 'wider' front to rear than others. Some may run while others may not with your present catch.

HA!  Fixed it!

Turns out it was the sear spring.  The center leaf that engages the disconnect was bowing into the magwell.  I pulled it out, straightened it a little and put her back together.  Disconnect still works fine (tested dry fire/cycle with snapcaps).  Mags drop free now.  

Good catch Matt_Q!
At least a good eye and some patience.
And the repair was free, that's a good price!