I would clean it with napthat or acetone and either spray it with primer or rough it up with some sandpaper if you want the herk to stick. I used it in my bed and it stuck great, but I roughed it up with an abrasive pad (the kind you clean BBQ grills with) and primed it first, worked out great.

1986 4X4, 1991 22RE, 5.71 gears,ARB Rear, aux fuel tank, 3mm O/S TB/intake, engnbldr cam, LCE header, magnaflow w/2.25 exh. custom 4 color paint job :-P 33X12.5 Goodyear MT/Rs