- 13/3/16
- 1,289
- 2,007
- 113
To know "for sure" you are going to have to open the back.
You can also put it on a timegrapher and note the amplitude. A 3235 will have a lower amplitude than the typical 31xx movements, but it's still not a "for sure" identification.
A lot of the VSF subs I've seen have had barely finger tight casebacks, so you're not likely to cause any problems opening it, and I definitely would not assume it's water tight anyway.