Regarding the profile gasket, if the gasket is new, the head skimmed and there is no corrosion pitting around the profile gasket area on the head face then it'll be fine.
On a full rebuild it's worth fitting the '93 onwards front timing cover that got rid of the chain idler gear. All metal oil filter housings were used until 1995 when they were changed for the plastic topped one.
The biggest issue with M42's now is crankshaft end float. BMW only used 180 degree thrust washers and many cranks now have worn through the lining and into the steel, machining a horrid wear groove into the crank rendering it scrap. Grab hold of the flywheel and push/pull it to see how worn it is.
M42 Rebuild
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