Tubular spoke tension too low? Fix it if it's not broken?

[hbn]

I'm fixing up a bike that has been standing for about 40 years. It was left almost unused shortly after its original purchase.
I haven't been able to go for more than a slow spin around the block, because the old tubulars were crusty and bulging, but the wheels seem to be true (Wolber Champion Tubular Rims).

The spokes feel very loose by hand though. Not sure if this may and cause som kind of problem.
Should i tighten the spokes a bit, before i glue new tires to the rims, even though the wheels seem true?

 

[mdvineng]

They need to be at the correct tension or you risk a collapsed wheel.

 

[jim haseltine]

I've found that spoke tensions have increased significantly over the years - probably because rims have become stronger which has allowed the number of spokes per wheel to be reduced. Spoke tension in a modern 20 spoke wheel is much higher than that in an older 36 spoke wheel.