I replaced mine last year with the ones from gbodyparts.com and they fit without any issue or modification. I was fortunate to have a stock throttle body with very little shaft to housing wear so mine sealed up with no leaks when going a smoke test.
Keep in mind these seals are not a direct replacement, you will need to make the Throttle body seal hole just slightly larger since the seals are slightly larger.
I know since the 1st one I ordered I though it was a direct replacement to which it will fit if you forcefully fit it, and then did a vacuum check and it was leaking around the Throttle Body seals.
The 2nd pair I ordered I used an Dremel tool with a Dremel 120 grit sanding band, and lightly going around the Throttle body seal area.
After a few light sanding I would check the seal area diameter using the seals itself for snug fit, no vacuum leaks.
There was a web site who does work and repairs Throttle Bodies, but I just found out that web site is for sale.
Mine were a bit tight but fit without modification to the TB. I used an arbor press to push them in and made a tool to keep the seal aligned and evenly supported when being pressed in. Making sure the seal bore has a slight chamfer is important too, will help get it started. I was surprised how well mine sealed up. I expected a slight leak just due to the nature of the application, but exceeded my expectations.
Thanks very much to Lockman, he had some seals he didn't need and sent them to me free. He paid the shipping and people like this is why the Buick form is still the best. Big thanks Lockman and if you ever need anything please don't hesitate to ask.