In Australia, the five speed & auto versions of the series one & two P910 [Bluebird] came with a 3.9 to1 diff ratio, but the four speed base model had a 3.7 to 1 ratio.

Five speed = overdrive output ratio with lower ratio diff.
Four speed = direct drive output ratio with higher diff ratio.
I have always assumed it was done this way so that the final drive ratio in the highest gear worked out pretty much the same for both.

I would suggest that the same applies to the US model 210 [B310]
There should be a build plate on the firewall with the ratio of the diff that was fitted at the factory.

The last line of vehicle build info is marked 'Trans. Axle.' & will show the trans model as something like F4W60L then followed by something like HB37
The code for the H150 differential is HA & the 'new improved' H150A differential is HB. The number is the ratio 'code' & 37 is for 3.7 to 1.
The 3.54 to 1 ratio that you seek will probably be shown as 35.

I suspect that you will be looking for a US model 210, coded as either HB310 or PB310 with a F4W60L & a HB35.
[H= A14 engine & P= A15 engine in these B310 models]