Morris-
There are a few differences between the floorwork for PLB, Gym Style Legs, and Legs & Glutes.
PLB-Only uses the stability ball, includes a variety of one legged glute raises on the ball, 2 legged hamstring roll-ins, inner thigh roll-ins, inner thigh squeezes, glutes tucks with heels lifted and knees facing forward, outer thigh lifts
GS Legs-Uses ball, step, and band. Tibialis Anterior (shin) work, one legged roll-ins, one legged roll outs/lifts, inner thigh lift/squeezes, glute raises on step w/ band, inner thigh work with band, outer thigh work with band.
L&G-Uses step and ankle weights. Glute tucks w/ step, glute raises, outer thigh sweeps, and then inner thigh leg lifts. I always add on the standing ankle weight work to this to make it more comparable to the other two. This includes weighted leg press and outer thigh sweep, standing quad extensions, and outer thigh lifts.
If you only have one of these, you can definitely sub one for PLB, but you might look into getting one of the others soon, to cure boredom if nothing else, lol.
HTH,
Mattea