Do a little research and you will find original 38 Special was just a hot if not in some cases loaded hotter than the mighty +P loads of today. So if you gun is rated for 38 Special it should be able to handle any +P ammo. Here is the best writing I have ever seen on this subject.
http://shootingwithhobie.blogspot.com/2009/01/p-phenomenon-by-saxonpig.html
Todays 38 Special standard loads are pretty much a joke. They are no better than the 38 Colt that the 38 Special was supposed to replace. The 38 Colt was loaded to get 750FPS from a 6" barrel with a 150gr bullet. That's about what standard loads are now getting. The +P loads are just an attempt to load to real 38 Special original load pressures and charge you an extra amount for doing so.