I just did this with a new -3 nose gear leg that Vans had matched drilled to the obsolete design one.
The motor mount had not been touched since shipment, and all of the holes were slightly undersize, but not by much. A 19/64 drill bit was a very loose fit in the hole.
My AN5 bolts measured 0.311.
If your AN bolts are a smaller diameter (AN5 bolts are 0.309 to 0.312 diameter), a close tolerance NAS bolt is 0.3110 to 0.3112 and could be used.
A 0.3105 reamer did the trick, and I was quite amazed at how easily it cut through the hardened steel parts just using a small cordless drill. Lots of oil used though.
http://www.use-enco.com/CGI/INSRIT?PMAKA=334-5056
When it was all done the AN5 bolt went in with a few gentle taps - it was too tight to push through with your fingers.
I did use a VAF idea and inserted the reamer shank into the hole first and pulled the reamer into the hole from the far side. It seemed easier to keep things centered this way.