RFE for W-2 forms, I-140 denial due to late Tax return?

My employer had filed an I-140 petition on my behalf with
CSC under EB3 category using LC substitution in July,
2002. Last week I have got an RFE requesting my
education certificate and salary receipts. This seems
to be a normal request however INS has also requested
my W-2 forms for last 2 years. Does INS typically asks for
W2 forms too?

Now I suspect that RFE for W2 forms is send since
I had not filed my last tax returns within the specified
time. I had just taken care...

RFE for W-2 forms, I-140 denial due to late Tax return?