Definitely yes! We use #2 x 3/8" long, pan head, slotted, stainless steel sheet metal screws for mounting a Cox Bee type engine to the Skyray plywood firewall.
On some other models, we may use same screw, but a 1/2" long, when mounting landing gear and the gear wire is not inlaid into the firewall. (To accomodate the greater depth that includes the gear wire diameter.)