I filled out a w/2 form but my boss issued a 1099 1.5 years later
Is this legal?
Can I dispute this?

Did you get pay stubs along the way? What were you furnished after the first year end?

i filled out a w/2 form but my boss issued a 1099 1.5 years later
is this legal?
can i dispute this?

Did the boss withhold SS tax, Medicare tax and income taxes? If not, you are not a regular employee. You can file Form SS-8. Determination of Worker Status for Purposes of Federal Employment Taxes and Income Tax Withholding. Firms and workers file Form SS-8 to request a determination of the status of a worker for purposes of federal employment taxes and income tax withholding.
http://taxipay.blogspot.com/2008/03/w2-or-1099-employee-or-independent.html