Without knowing what the OEM steps on your 2013 Forest River Flagstaff Fifth Wheel is, I won't be able to say if the:
-Flexco Manual Pull-Out Steps for RVs - Triple - 8" Drop/Rise # SMFP-3100 will fit or not.
To determine if these will fit, you can just compare the mounting dimensions of these steps to the steps you already have.
These steps have a mounting bracket dimension of 27" wide x 14-1/2" tall x 12" deep, so if this matches what you currently have then this'll work great for... view full answer...