Yes, On the 401 A, the throat plate or needle plate raises to just above the feed dogs.. by using the UP position it is still locked on the machine, you have to move the lever all the way left to unlock the plate.. I have been sewing on the 401A since 1960 or 1961 when I got my first one, I now have a second one for back up.
I have never had to adjust the pressure foot pressure for FMQ as my free motion foot does NOT touch the fabric, it is like 1/8 above the fabric so it does not interfere with the moving of the material.
I actually have 6 Singer Machines in all. Treadle, featherweight from 1952 ( my 11th birthday present) 2 of 401A, ( free motion on it) Singer Golden Touch & Sew 750, Singer Confidence Quilter 7469 (which I use daily now) I also have my Bernina 1630 which I loved for Heirloom sewing.