That's a nice lookin M28 you got and a real good price too. As far as some history, check the factory Letter of Authenticity I received on my Model 28-2 4" HP.
Mine is a October 13, 1975 shipment to a Maryland Police Supply outfit.
My pics show the "brush blue" or "satin" as some call it which was no frills subdued finish for duty weapons. The pic of an original advertisement was borrowed from another post on the forum, but shows that the service magna grips were on the 4", and it seems the 6" got Targets (either football cutout, or speed loader relieved). If you've got no rust or pitting under the rubbers, you may want to search the Classifieds on this forum, or be on the lookout for original N frame Targets to return your Model 28 to near original.
I'm like you.....these are real honest to goodness shooters that deliver right to point of aim as long as you do your reasonable part. The other pic titled Trigger Control helps keep your focus.