The old 1981 version Briggs sidevalve workshop manual just says to oil the crankpin, and the piston/rings prior to fitting the ring compressor. Wouldn't hurt to give the mains a wee squirt, either.
It does mention using a 'valve guide lubricant', B&S P/No 93963, but this has been discontinued.
Going by its MSDS, it was a Lead-based metallic antiseize, containing ~70% metallic Lead powder!
Engine oil will be just fine there, too.
