I work at 3M and although we don't make the tape at our Plant, we do use VHB tape for laminating optical fiber in duct. I would suggest that you wipe the surface with Iso Alcohol and warm it with a hair dryer prior to application. Press and hold for a minute. We use the # 4914 VHB which is gray and about 1/8th in thick. It takes 24 to 72 hour to completely adhere. Wipe it with iso and warm it and you should be good to go.I'm not sure what they used but this is what I'm thinking I'll buy when I go to add the SRT 8 spoiler to my R/T.
3M VHB Heavy Duty Mounting Tape 5952 Black, 3/4 in x 15 yd 45 mil
Take it easy