Do the bars have numbers stamped on them? That will tell bar length, chain pitch, gauge, and number of drive links.
Do those chains you want to use fit the current bars and drive sprockets? If not, you may need to replace the sprocket for them to work. Easy enough to do if there is a sprocket that fits both your saw and those chains.
The last step is finding a bar with holes that line up correctly. Some of the sellers like
Bailey's have a search tool.
I usually use
Oregon's search tool as I usually use Oregon bars.
That says a 70E with 20" length, 3/8" and .050 chain uses Oregon part 200RNDD196
All of these search tools assume stock sprocket. If that was changed at some point to a different size, the number of drivelinks could be a mismatch.