Since (in the US at least) the IR is a rating on your licence and not a licence in itself, it will not technically overcome the restriction on your converted licence.
No, when you pass the IR, your licence is endorsed "Single engine instrument airplane US test passed" [or ME], so the restriction doesn't apply.
Be aware that you must have completed ALL the minimum requirements for the FAA PPL before taking the IR check ride. This includes 3 hrs dual night. Not a big deal, unless the examiner spots it on the day of the IR [which he will], then you loose the test fee, or a portion of it, and can't take the test until you have these required hrs [happened to me].
EA