Seriously, from the description,I believe you will need to dust a bit off the safety's block surfaces. VERY IMPORTANT QUESTION: Do you have the Kuhnhausen, or similar 1911 manual describing how to fit a safety?
If not, I would strongly suggest you pick one up before going further.
It's been about 5 years since I touched a 1911, so...
You'll need to "wiggle" things to get your safet back out. Once you do, you'll probably see some scratches on the block surface, which indicate the areas that will need filing. You can't just zip off metal, the angles are modestly important (get the manual), but, with the safety removed, when looking into the hole where the sear and hammer surfaces are visible, you will see the pieces that the safety needs to seat against when in the raised position.
I "learned" safety fitting by replacing a sock safety, so I had a model. With the parts kit, you really need a manual. Even if you pull the safety from another 1911, the safety cust may be in dramatically different places and angles, because of tolerance stacking and manufacturing differences.
Sounds intimidating, but it isn't bad, just take your time. BTW, while you have it open, insert a mag in the well, and make sure your trigger bow doesn't rub on the mag. That can be 1/3 of a good trigger job.