MrBill,
The Standard Catalog of Smith & Wesson shows that a Model 38 is worth $350 NIB (with box, manual, etc.) and $300 in Excellent condition as you describe your specimen. So it's a fair deal, but not a bargain. That said, the value of these little guns does seem to rise every year.
If the wood grips have a clear "diamond" around the grip screw or the serial number lacks a "J" prefix, it's a pre-1969 gun. A pinned barrel dates it as a pre-1983 model. A matte-blue appearance would be 1993 to 1999.
The Model 38 is the original Aluminum alloy frame and if subjected to a lot of +P use the frames can stretch enough that the cylinder fails to lock up correctly. Practice with standard pressure .38's, carefully sight where your favorite +P hits with a minimum of shots. The +P's should be safe to shoot but you'll "wear out" the gun much faster with them.
The deep blue/black finish on the Aluminum frame is, I think, most likely a deep blue/black anodizing with the cylinder and barrel finished in a dark bluing.
Pocket lint can build up in the hammer opening, however I have yet to find enough of it building up to prevent operation if you blow the lint out daily.
Personally, I like both the Bodyguard and Centennial models. The Bodyguard, IMHO, seems like the "professional's gun" (maybe because the first one I ever saw belonged to a 20 year veteran police sergeant).
If possible, find some standard pressure 158gr LSWC (or RNL if you must) factory ammo to check your sights. As I recall, most of these had their sights regulated for a 158gr .38 Special round.