Remember the Glock polygonal rifling is a different form from standard rifling. The SAAMI drawing says the standard for 327 Federal is rifling that is 0.0045" deep. This should be clearly visible. Open the cylinder and place the white back of a business card over the recoil shield (the flat surface that includes the firing pin hole). With good light on that, you should see the rifling well.
If you cannot see the rifling well, you may have packed it up with fouling. Clean the gun thoroughly. I recommend Bore Tech Eliminator as your general purpose cleaner. If you have significant lead fouling, you want to use NO-LEAD. It reacts with lead to turn it to a crumbly substance that patches out. Most folks scrub it out, though, with strands from a 100% copper scouring pad, like Chore Boy brand (caution, most copper-colored pads are steel with copper plating; use a magnet to check) wrapped around an undersized bore brush. The Lewis Lead Remover is also still made and is another mechanical approach.
If you get it clean and still doubt the rifling, slug the barrel or carefully measure the distance between opposing lands and opposing grooves with the ID jaws on your caliper. The difference should be 0.009".
