(vintage) 5thW hitch

[Freedom55]

I am trying to find out if the hitch that came new with my new 1978 3/4T Chevrolet is still legal for use today. Both are in top notch condition and the unit still looks new so I would like to continue using both. I towed a 27' camper, weighing 1850 kg on both the truck axle and the trailer axles, in Alberta, for years with no incidents. Well past the time that hitch design changed and were re-configured to bolt to the frame rather than just the sheet metal.
That trailer is long gone and the hitch still lives in the Chevy but I need to know if I have been breaking the law for all these years. SGI informed me that their rules changed in 1987 and would not be deemed safe, therefore uninsured, yet I have towed that trailer more than a few times into SK.
Can you help me out? Does anyone know the legislation or the appropriate authorities to contact? Thx

[Reeves1]

D.o.t.

[HILLYBILLYBARRY]

Got picture is it over the fender 5th wheel i work for a hitch company ? So im a hitch guy.

[Freedom55]

Yes. The hitch has two pieces that bolt to the floor right against the wheel wells then again on the top of the wheel wells. The main piece then lays across the two members and is pinned in place. Like the 240 litre propane tank, I have used steel plate washers to secure the grade 8 bolts. I would require a monster flange if I were to bolt to that instead of the tin. I was quoted $1400.00 hitch shop on 42 ave se and I'm not sure a new style is available for this frame. Thx for any info.