I have seen some awful jobs of installing cab roof panels. This one from the 1070 BK was missing bolts and glued down with 4 different sealants and still leaked. I spent a couple hrs cleaning the mess and installing all new hardware. A new gasket is easy to make by installing closed cell foam strips and using a old hot screwdriver to melt the bolt holes. I install a bead of caulk on the front and rear of the roof panel after it is fastened down. Not because it needs it to seal the roof, but it keeps the gap from filling with dirt and moisture and helps eliminate a rust problem. The cab filter is dated 1987, I think it is time to replace it also, LOL. Rod.