On the one hand, I forget which one I bought - sorry, most were similarly outfitted. And don't have the same appearance of the XM 177 or as we called it in USAF, the GAU. What to change, in general -
I replaced the plastic "brass deflector" with a plain old forward assist. I shoot lefty and no gas or brass issues from that. The forward assist "assists" nothing but looks right. Then replaced the "half dust cover" with a genuine. The unit probably came with the larger handguards, those were replaced by the XM type.
I added a fake gas tube from the front sight base through the handguard into the receiver. My version came without the tube or the cold rolled pin through the front sight base - bugged me to see daylight in the pin hole and no tube going into the receiver.
With the dust cover closed it's impossible to tell this rimfire from a 5.56. Which is what I wanted.
Model One sells their 22 lr uppers with a full dustcover, but no forward assist - integral brass deflector, it would appear. And an 11" bbl with welded on FH.
https://www.model1sales.com/index.cf...ategory_id=320
Biggest challenge for me was the fake FH. My version has the 16" barrel with a slipover FH. Which is fine, but it doesn't exactly match the lines of the original.