I was dumb

Brewing a Schwarzbier. Everything went by the book. OG .054, (Recipe stated .051) Immediate bubbling 2-3 hours post oxygenation. Fermented at 50degrees for 10 days, then 65degrees x 2 days, then a month at 42 degrees periodically draining the crud from the bottom of the conical.
This is where the dumb kicked in:
I added the sugar before I got the final Sp. gravity.
Any point in taking the S.G now or wait til it has carbonated, take a measure and let it go flat then take S.G. Will it get me close in the ballpark?
Target FG = 1.013

Go ahead and take the reading,the priming sugar may throw your reading aff a bit but at least you have a really close idea! 1/2 cup or so of sugar would have negligible affect on the reading.

Good news. After I had drained crud from the bottom of the conical (and along with it some beer) BEFORE I added the sugar solution I then placed the container of beer/crud on the counter and forgot about it. Well, the crud settled out leaving clean beer, enough to get a SG which was .011, the target was .013. When I rack here in the next few hours I'll get a SG on it with the sugar in it and let you know the outcome.
Thanks for the assist.

FYI:
RE: I was dumb
SG before I pitched sugar = 1.011
SG after I pitched sugar = 1.013