The proper side-mount peeps, that fit your rifle's factory prep holes, are the Lyman 66A and the Williams FP-94/36 or the Williams 5D-94/36.
MidwayUSA & Brownell's both usually carry them, but are sometimes out of stock, especially during hunting season or around the Holidays.
When you order a peep, don't forget to also order (or make) a rear barrel sight dovetail slot filler blank - because the rear barrel sight should be disappeared to give a clean sight picture through the peep.
FWIW, There is a pictoral/tutorial thread here, or in the leverguns section, on making a filler blank fron an old rear sight base.
.