Well, regarding the bezel.
@pitpro is right IMO. This type with "the closed five" and larger font is typically seen on serial 26.3x, .8x and .9x - that is 68 productions. But also on a few 27.x serials.
On serial 24.71x I would like to seen the type with "the horizontal one" (left one below) or at least "the open five" (right one below), the later most often seen on serial 25.x, but also on a few 24.x
24.71x is a spring 67 production.
But again, production of these 3 mentioned types are within a timeframe of about 24 months, so I'm not saying that the OP's bezel couldn't be correct/ original mounted for the serial and this watch.. I just don't think so ;-) But it's still a SM300 2. gen correct bezel and in pretty ok condition besides the nick at 20.
The lume on dial and hands not so much
Here's one of mine with serial 24.71x
Click to expand...