anchor point yes since the distance from the jaws to the d-loop will be different, but id say no on actual DL since distance from nock to rest is constant.
That being said your DL may need to change to accommodate a constant anchor point if that anchor point is correct for both styles of releases
Technically, it will not change your draw length (distance from throat of grip to nock point + 1 3/4” I believe), but it could very well change your anchor which can have the same affect. As stated above, you may be able to address the difference with a change in the length of your d-loop.
Just went through this exact same thing. A couple of items to be prepared for:
1) If its your first time using a thumb release, grab a release add and spend some time practicing. This will help your transition from wrist/index to the thumb. Will also help you not drop the release.
2) The Stan is awesome. Its going to take you some time getting use to it, but when you do, you'll love it. Took me about a month for it to become my new normal.
3) Your arrows are likely to impact in a diff spot on the target. Mine were right. I hung with it for a few days and confirmed that I was pretty much 6" right. From what I gather, its the diff anchor, diff pressure on the bow string.
Wont change your draw length but will change your anchor a lot.
If i go from my Wrist rocket to my Carter Wise its 3" at 20 yards to the right.
You can tinker with your D loop to get it more consistant. Just set everything up to be consistant.