Can we think a little out of the box here?

Why not credit these miles (from the MR) to no program. You can request the 1K desk to take out the mileage earning part of the input (something like TQNY or....) Usually only only an experianced agent would KNOW about the diff (earning / status for upgrade) MP # inputs. IF you get that agent, get him / her to remove the mileage earning part of that input and leave it blank.

By 1st JAN, you will know if your 1K sticks. If it sticks, good for you. Go to .bomd (not immediately, but later, later, later I mean like after 6 months) claim the missing miles. By that time, you migh get credited for the current year. I have had some miles from previous year got credited (automatically) in the new year a/c and I had to call them to bring it to count toward previous year. With United, it is all gamble (although in a good way)