Harsh reality lesson"drop in" is a sometimes thing particularly on a 1911.
The fine print will say "should be installed by a competent gunsmith"
I'm not saying anything bad about RIA,I think they are good value,but even if it were a Colt frame,1911 was long ago,methods and tooling have changed,and guns used to be built by craftsmen.The tolerance stacks require fitting.
If you protest,what you will be told is"Well,that one of them foreign copies...."
Expect to fit a safety,and do not expect your first will come out right.
You can turn it over to a smith,and you may,or may not,get a good job.
If you do it yourself,slim chance you will get a safe,functioning pistol stumbling in the dark.Its an education that will require some investment on your part.You will need references,a few tools,and likely some "start over" parts.And,patience.
Kunhausen's 1911 shop manual is indispensable.Wilson sells a DVD armorers course.Look for the one or two DVDs that cover trigger job and safety fitting.
If you think you want a different trigger or grip safety,etc,do it all at once.There is a fitting sequence,the toe bone connected to the foot bone,the footbone to the ankle bone,etc.
Good luck.