Yes, the "numbered guns" 60, 15, etc. Can safely handle +P.
I recently purchased a model 60 which is practically unused. It's chambered in 38 special, however it looks and measures to be almost identical in size the the 357 version with a shorter cylinder.
So, can it safely be used with Plus P rounds?
My 1990 Model 640 .38 Special is etched "Tested For +P+". Your 60 will be fine, but a lot of knowledgeable folks say if you shoot a lot you might want to practice mostly with standard-pressure ammo and carry +P.
thanks everyone for the responses!!