In recent times, it is not usual to take only 4 biopsy samples.
Personally I would obtain a 12 sample biopsy and request 2 opinions on the reading: Biopsy readings are subjective, so good advice is also to obtain the 2nd view as you will be basing your treatment decisions on the results.
Gleason scores with 3 as the main figure are very usual results and are obviously not the most agressive scores one can have.
It is very rare for someone with a PSA under 20 to have bone problems.
Once you put it all together you can then consider the various treatment options.
While many people and doctors have thier own prefered treatment option, the facts often indicate that several treatment options can yield similar results, so it could come down to personal preference.
Most here will advise that selection of your doctor is the most important consideration, regardless of the treatment chosen.