Hull number 1784 - need to ID month

Hello - prior owner painted two coats of paint covering up the 12 digit hull ID. But, I do know my hull number is 1784. It is stamped on the metal plate on stern and on original main sail and bag. I have no papers or documents with 12 digit number.

Does anyone have a similar number? I think maybe mine was built in 1987 based on reading of other threads.

I could try to carefully strip paint on stern to reveal the 12 digit number, but that is iffy.

Thanks for your response.
Wayne