You did indeed see an early Combat Master, as far as I can tell. The early barrels were Colt, or militry surplus; some even National Match, that had cones sweated over them with a brazing compound. Then they were sent off to be hard chromed; which was polished to a shine.
For a while the Detonics hammers were Colt Commander hammers that had the lower rear back of the spur cut away and sanded off. They had a "J" shape to them. Later, a genuine "J" shape was adopted, (investment cast), later to give way to a semi"J"shape, (also investment cast), that was somewhat filled in to prevent the spur from snagging on clothing, or what have you. That hammer became the standard thereafter, at least in the Seattle/Bellevue production Detonics.
Service Master II? Do you mean Series II Servicmasters from New Detonics in the Phoenix, AZ plant?