Aside from what Stuart has pointed out,there are some other things to look for.Now, we don't know how much knowledge you have of Triumphs and that brings me to the question:How do you know it is clearly a 1970 model aside from the use of the Pre-OIF frame ?
Does it still have the Spring Gold paint?
Are the fenders painted in Spring Gold with the black stripe and gold lining ?
Are the front engine mounting plates in place (triangular plates with two bolts mounting to the frame and one to the front of the engine case?
Also,if you remove the primary cover, does the case contain the three small breather crankcase vent holes for oil/built up pressure to pass through into the primary and an elbow on the top of the inside primary case with the vent pipe leading up to the rear fender?
If you take off the timing cover, do the timing/camshaft gears have two threaded holes in them for attaching a gear puller?
Just a few things for you to look for.A picture would also be great.Hope this help? :-)