So your on speed, stabilized sink rate, and you're two dots high. Do you push over for the glideslope and then throttle back OR do you reduce power slightly and settle to the glideslope?
No question: put the aircraft back on the glideslope with the stick. In all probability, the speed will not increase at all because of the relative amount of drag, certainly not enough to worry about. And if it did, the speed would soon settle back to where it was before when you were back stabilised on the GS.
If you did this is a C150, yes, you would see a increase in speed and yes, you probably would have to throttle back a bit and yes, you could descend back to the GS by pulling off the power. But we're not in a C150. The 737 by virtue of it's pitch/power coupling may also let you get away with using the throttles to fly the GS, but that's trick-flying and I contend that it's not the speed-stability effect, it's only because of the underslung engines.