Washburn serial dating
You can confirm the year of manufacture by visiting our guitar archives reference pricelists/ catalogs.
Instruments with serial numbers that have 5 or more characters are from the late 1980's-2000's Instruments with serial numbers that have 5 characters or less are typically from the 1980's.
For example, 8901827 indicate the instrument was made in 1989, 1988, or 1998.
Only reservation is that the finish, while a nice colour and well-applied, is rather thick and glossy.
I've seen the more recent Chinese incarnations of the M3-SW, and while the specs read similar, they seemed rather lower build quality and more generic than mine.
Instruments with serial numbers that have 4 characters are from the 1970's and early 1980's.
For instruments produced after 2010, usually the first 4 digits can indicate the year of manufacture.