The payer is not permitted to obfuscate it's TIN on a Form 1099-R. Perhaps the obfuscated TIN is your own SSN, which should be obfuscated, and you need to look elsewhere on the form for the payer's TIN (it's the EIN of the entity that issued the Form 1099-R). If the payer's TIN is truly obfuscated, you should contact the payer to obtain a properly prepared Form 1099-R.
If the Form 1099-R includes any tax withholding, entering a payer TIN other than the correct one might cause the IRS to question the validity of the tax withholding being reported.
