Sajhamitra,
I know you are in legal path and as per my lawyer, he said that, it is true illegal but USCIS do not have access to IRS records, The only tax information USCIS will come to knows is only what you provide them during 485. If USCIS needs any thing they will contact you directly. But there is no need to submit any tax related document. Uscis will check criminal record and your constant job history with your employer who holds your H1 once 140 is approved. If you say USCIS really do check with IRS, they could have rejected/ denied many labor, 140, 485 for those who had worked using SSN during F1 status in Summer time illegally.

So i will definitely reply you here once i get my 140 in some more days.

Thanks