I've never used a break in additive. Any chance it has colored your oil? Rotella alone should be OK.
Could be condensation depending on how many times your shop went from freezing to toasty warm if in fact your shop doesn't have full time heat. If you have anti freeze in the engine the easy test is just get a touch of oil on your finger and taste it.
You said some of the rockers were tight for side clearance. Not sure about SB rockers but BB has different offset for intake and exhaust.
Check all your pushrods for interference with the heads. If they are hitting they will be shiny where they hit.
