Exogenous testosterone (any sex hormone, really) does carry an increased risk of blood clots from what I've heard.
I have had top surgery, complete hysterectomy/oophorectomy, plus a hip surgery due to injury since I've been on T. The only time I was asked to hold injecting was with my hysterectomy, she recommended I hold my injection 2 days longer than I was due (I was due to inject the day of surgery). I haven't been asked to hold or abstain from my injections any other time.
I am due to have metoidioplasty with scrotoplasty and Vaginectomy 6/15 and haven't received my full pre op instructions packet yet but I'm not sure if they will require it or not. As mentioned, worst case scenario would be you'd be asked to hold a week or two pre-surgery and/or a week or two after. It wouldn't be for any substantial time period.
It does depend on the surgeon, from what I've heard, though.