Briggs and Stratton Vanguard oil problem
 

I have a Briggs and Stratton Vanguard 16 hp engine in a Cub Cadet 1641. After correcting all of the wiring problems it started up and ran . I noticed after it ran for a while it was showing a little smoke on quick acceleration. Before starting it I changed the oil and filters also the spark plugs. It was running rough , I took the air cleaner off and saw about an 1/8 “ of oil in the base of the air cleaner. Removed the air filter cleaned out the oil and it ran better. Oil started coming back into the cleaner from the crank case vent tube. I removed the vent cover and checked the reed valve no apparent problem. Doing some research here on OCC the problem could be a bad head gasket (s). Before I take the heads off do you agree it is probably the head gaskets?
Some measurements and observations:
Compression 125 psi both cylinder.
Push rods and guides look good.
Valves were not out of adjustment
One valve cover gasket partially missing ?
Dip stick tube tight.
Engine model # 303447 type 0447-01 build 93101611
Hours on working meter 302
Thanks Dave