As with most weapon construction questions, you will need to refer to specific chapters as to whether they would or wouldn't pass a specific weapon.
In general, the specific coating used on the outside doesn't necessarily force a chapter to call a weapon one type or another. The rules pertaining to "latex weapons" are generally in regards to storebought latex weapons, which have a significantly different construction method than "homemade" weapons. The Alliance rules state that "alternative weapon construction techniques may be used" - you can always *try* to get something passed by your chapter and see what reaction you get. If you have a weapon which is in every way a boffer weapon as per the construction guidelines in the rulebook, but with a latex coating, it is probably more akin to a boffer weapon than the rules that refer to latex weapons specifically.
At the end of the day, no matter what, the Alliance prohibits thrusting on blunt weapons or weapons without a thrusting tip. Your local chapter may interpret the weapon guidelines as prohibiting thrusting on all weapons with a touch of latex on them, or it may allow thrusting with latex weapons that have Alliance-safe thrusting tips on them. The weapon construction rules are written in such a way that ARC cannot make Alliance-wide rulings which absolutely allow or prohibit any specific alternative weapon construction technique.