Can't be answered without a DETAILED description of ALL markings, barrel length, finish, grips, sights, box, accessories, papers, condition.
Impossible to answer without the serial number. The serial number should be on the butt.
You did not provide the serial number. You will have to call S&W to find out.
Impossible to answer witout a DETAILED description of ALL markings, features and condition.
50-100
It is any number of the form (38s*k)/k where k is a non-zero integer.
actually you can use 38 special or 38S&W (shorter case), but you cannot use 38 special in a 38S&W pistol. in your case 38 special
The coordinates 38S 145E correspond to Melbourne, Australia.
2,19
Unforunately, just the serial number does not give us much info. Serial numbers are NOT unique- more than one gun bears 3635- and H&R made thousands of top break 38s- in dozens of different models. Link below can give you some info- read all the way to the bottom for some of the model info.
RG firearms were typically low cost/low quality items. Depending on model and condition, these may sell for $25-$75.
3/8 = 0.375
There were two styles of N-frame .38s, the fixed-sight .38/44 Heavy duty, and the adjustable-sighted Outdoorsman. Since all N-framed revolver frames made and numbered were of various calibers for later assembly, it is difficult to pinpoint dates of manufacture for any particular caliber or model. The serial number provided, 43138, would put the probable date around the mid-1930s. Not enough information was supplied to evaluate the current value. Condition, and originality are very important here. Roughly, a decent example, if original, could fetch $400-500. If refinished, or not wearing the original stocks, the value could decline by 50%.