I have a chance to pick up an upper from a early Sporter 9mm , its looks identical to the SP1 upper with the exception it has the half port door and deflector shield ....any issues removing the half door and swapping out for a retro ejection cover and rocking a Retro build with it ??

No. The biggest issue is that they aren't milled for a gas tube and quite a few aren't milled for the cam pin either.

Sell the 9mm upper on EE and get yourself an SP1 upper and be done with

i have a new Fulton armory non forward assist upper Id trade you for your 9mm receiver sounds like a win win sence im using it on a 9mm build lol

What he said.

You can sell the 9mm for more than the other will cost you...

I bought a Brand new Colt A1 9mm from Brownells around 6 months back for $189, then won an older A1 SMG  XM Gray Colt 9mm upper on GB in an open bid auction (it had complete 9mm door assembly & Sight wheel) that ended at $125 several months ago. There's a few guys out there asking crazy prices on GB but they are not selling. I ended up selling the new one and used the SMG upper for my build, as it was mint and the color matched my NDS lower, When selling the new upper, It actually was a hard sale on EE that I ended up bumping the thread for right at 2 months, having to cut the price and took a loss. Other than us Retro guys most are wanting flat tops for 9mm builds.

I'm building a 9mm and would be interested in it.

I planned to keep it and build a 9mm DOE . ..thanks for all the purchase offers but it's not for sale.

This^^^^^