If it has a shape in the Astral, and the spirits mental skills were sufficiently high, would it not be reasonable to assume they could reason out a weapon by it's astral shadow?
That presumes the shadow has a real correlation with the physical shape.
You can't tell a troll adult from a human baby in astral, so I don't see how a gun's shape is easily discernible from a clipboard's shape.
What? I have never seen anything to indicate you can’t tell a troll shape from a human baby or even a troll baby from a human baby apart in the astral.
What says that you CAN?
Sex, Age, metatype, and many other things are decidedly NOT on the list of things you can discern via assensing.
As a matter of fact, once you start saying you CAN see these things, you get into total landmined territory. What's the "true" gender, according to the aura, of a biological man who's a trans woman? What about elf/ork poseurs? No matter where you draw the line, other than "you flatly can't tell these things", is a lose/lose.
Furthermore, it's been established for a long time now that your aura extends "out from your body and through your clothing". This is the exact rationale for why you can still target people inside fully-encompassing armor with spells. Since the clothing (and presumably, other carried gear) is INSIDE the aura, from an astral perspective, it's somewhat hazy to me that you could see any carried gear at all.