coffinhandler:
Your Model 28 Highway Patrolman was manufactured in 1960 or 1961. Serial range for those years was S207000 to S219999, so 1960 seems likely.
The Covertone:
Your gun is a Model 34-1 .22/32 Kitgun, not a Model 64. The .22/32 refers to the .22 being chambered on a frame originally designed for the .32 S&W long cartridge. The -1 refers to a change from the .32 sized I frame to the .38 special sized J frame. Your giun was manufactured in 1980 or 1981. Serial range for those years was M130001 to M160000 so 1981 seems probable.
kingpoppacap:
Your Model 19-3 Combat Magnum was manufactured in 1971. It was built on the Medium sized 'K' frame, originally designed for the low pressure .38 special cartridge.
The Model 27 is a different gun, the original chambering for the .357 magnum, using the large N frame that was originally designed for the .44 Special cartridge.
The Model 19 is a much handier gun, suitable for the patrolman, the Model 27 was originally promoted as a hunting firearm.
Because the Model 19 is based on a smaller frame it can be damagred by some faster ammo. I suggesat you read this:
http://www.gunblast.com/Butch_MagnumLoads.htm
I think the issue is the smaller faster bullets leave the case before engaging the forcing cone and are therefore travelling a lot faster than the heavierr longer bullets, giving the forcing cone a much heavier jolt.
Simple solution is don't shoot 110 or 125 grain magnum loads in your gun. Any .38 special or 150 grain or heavier magnum round should be fine.
31237 & G1 stampings are assembly numbers, used to track parts in the factory. They have no meaning after the gun is completed.
Mocup:
Your Model 27 .357 Magnum was manufactured in 1956 or 1957. If it has the model number stamp then 1957. Ifd no stamp then 1956. Model numbers were introduced in 1957. Prior to that it was simply The .357 Magnum.
Your Model 29-5 .44 magnum was Manufactured in 1992.