I have three bikes, all 1970s, all 531. There is a noticeable difference in flex/whippiness between them, to the point where I briefly had concerns about the integrity of my Raleigh's frame. No issues, of course. Ride your bike off the trainer, see if you like it. If you do, proceed with restore/refurbish. Easy-peasy.
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A race bike in any era is a highly personal choice that at its "best" balances the requirements of fit, weight, handling, durability and cost tempered by the willingness to toss it and oneself down the pavement at considerable speed. ~Bandera