The filters (clear and ND4) that come with the Sony/Minolta reflex lenses are called drop in filters and they are glass. I once found some for sale on ebay but they were very expensive and they are now very scarce.
The front of the Reflex lens has an 82mm thread and will accept any 82mm filter. The lens hood will then screw onto the front thread of the filter. I have tried this with the 82mm clear filter that comes with the Minolta 300mm f4 HS APO with no problems. The drop in filters for that lens do not fit the reflex and are even more scarce and VERY expensive, $300 to $400 for a C. Pol.
I am almost sure that Circ Polarizers will work on the reflex, but not certain. Turning the 82mm filter is no problem, just turn the hood or leave the hood off. However, lengthening the hood by the thickness of a filter may cause some vignetting. The only filter I have any real doubt about is an IR. The 82mm filters are, I think, the largest of the easily available and reasonably cheap filters available.
Sony A7, A850, A77, A700 || Sony>> 70-300G, 28-75 f2.8 SAM, 16-80CZ, 50 f1.4, FE 28-70 OSS, FE 24-70CZ f4 OSS, LA-EA4 || Minolta>> 300 f4 G HS, 200 f2.8 G HS, 100 f2.8 (D) Macro, 50 1.7, 28 f2.8, 28-135 f4-4.5, 70-210 f4, 500 f8 Reflex, TC x 1.4 HS, TC x 2 HS. || Sigma> 21-35 f3.5-4.2.