By having all the strings replaced will the tone/timbre of the instrument be different?Would you use strings made by Grotrian?
Through the looking glass of 70 years of gradual aging, the result will be a marked change but still faithful to the originala. There are several custom bass string makers in US and Canada, like J.D.Grant, that are better suited to recreate a set of new bass strings from the originals...piano factories are mostly set up to make their current production...the Grotrian 185 is several designs previous.
FWIW, if you need a replacement for a Yamaha bass string here in the US, Yamaha suggests you call Mapes in Tennessee, and they've even given Mapes their scale specs to make it easier. Just a healthy perspective on the global market of small production. Compared to other widgets, the sum of all new pianos produced would seem like a drop in the ocean. You don't always go to the source, you go to the specialist.
As Peter Gray mentioned, San Fran on the whole seems to preserve pianos better than may climates, so my fingers are crossed for your piano. The hard part about piano repair is finding the appropriate starting and stopping point that will = satisfaction.
And as Ed McMorrow mentioned, before any of the above work is completed, the pinblock is foundational. If it's healthy, then a restring is reasonable. If it's cracked, delaminating, sagging or has wallowed holes, then a new pinblock is needed. It's not possible to see all sides of the pinblock with the harp in place, but evaluating what can be seen will usually spot obvious red flags.