Factory reinforced heavy duty frame

[JDJR]

I am looking at a pair of running boards for my 1989 F 250 7.3 idi. The product description states the following

APS iBoard (Silver Running Board Style) Running Boards Nerf Bars Steps Step Rails Compatible with Ford F-Series Bronco 1980-1996 Regular Cab (Will Not Fit Factory Reinforced Heavy Duty Frames).​

How can I tell if my truck frame is a factory reinforced Heavy duty frame?

 

[FrozenMerc]

You have an F250, you will be fine. The factory reinforcements was typically limited to chassis cabs on F350, F450 and F550 units with the highest GAWR.