Thanks for the replies.
Kimo, I am not sure what you mean here when you say this is a "generic" cachet. "Germany Surrenders to the Allies" is pretty specific to VE-Day, and this cover is cataloged in Sherman's catalog of WW II patriotic covers. That doesn't mean that the cachet could not have been applied later; as I indicated, I think that was typical of WW II event covers, even by producers such as Fidelity or Fluegel. But the ones I am sure where this is the case always have, to my recollection, Washington, DC, postmarks. (Well, maybe some Victory, VT postmarked covers fall into this category.) But against the view that the cachet was applied after the fact is the way this cover shows all the marks of having been postally used. The return address appears to have been written as if the cachet was already there. This just doesn't look like a cover postmarked in the Philippines and then sent to Crosby for application of a cachet later. I'm reasonably confident the cachet was already on the cover when it was addressed, censored, and postmarked.
bookbndrbob,
There are two dates celebrated as VE-Day, both May 7, and May 8. The act of military surrender was signed on May 7th in Reims, France and on May 8th in Berlin, Germany. VE-Day covers with either are easy to find, though May 8 are probably more common.
hy-brasil,
I'm no expert, but the handwriting does not look the same as on some Crosby covers that I think bear his handwriting. I just now took a look on
ebay and see two more examples of this cachet:


I don't think these are "Crosby-serviced" covers. As I wrote earlier covers I'm pretty sure that he serviced typically have Naval or San Pedro, CA postmarks.
The widespread existence (geographically) of covers with this cachet further reinforces, in my mind, the likelihood that the covers were prepared and sold ahead of time. Wikipedia claims that the term "VE Day" is known as early as September 1944. Certainly by early 1945 everyone knew that it was just a matter of time before Germany would capitulate. So I don't see why this couldn't be the case.
Again, thanks to all.
Basil