I wouldn't bother with this one, as the geometry is now steepened and with (apparently) no needed corresponding reduction in fork rake (needed to preserve the critical "trail" dimension).

As with all old and questionable bikes/parts though, I always consider loading, and the relative heft of the rider who will be riding it, the road surface conditions on which it might be ridden, and for how long(?). All of these factors can weigh quite heavily on the remaining fatigue life of hard-used, rusted or compromised structures.