Here are a couple new pics of my T91 clone. I had a local gunsmith install the correct gas block on my upper, took a total of 25 days from when I dropped it off. The gas port in the barrel was allegedly undersized and would not cycle properly, I found the correct gas port spec and gunsmith enlarged the port and now functions properly with a standard buffer. The one last thing I need is to complete my 80% lower and it will be totally done. Also shown is a T91 magazine with the witness holes, all T91 parts courtesy of T91 tactical.
Looks good. You might want to consider replacing that roll pin (pinning the gas block to the barrel) with a more secure solution like a tapered pin or even a regular steel pin. It's probably not critical unless you want to be absolutely sure that the front sight post doesn't wiggle even a little bit.