I'm not entirely convinced that it is in fact Mr. Cullen that did sign it.
I spent a few minutes browsing online and a few things caught my eye:
The way the P is signed. I haven't seen another signature with so much of it signed through the upright.
The E is too square and not smooth enough (look at the whole signature, it appears to stop and start while the marker is resting on the trailer)
Mr. Cullen's signature has four raised uprights to emphasize the U, L and L, this only has two. And finally, notice the correction of the R in Prime. Surely he would know how to spell it properly.
I definitely respect your view, and of course it passed my mind that this might be fake.
However, this autograph was doen with a lot of certainty, and without obvious hesitation in the strokes. If I was to forge someone else's autograph, I'd probably be a lot more hesitant about scribbling it, especially with permanent marker on a G1 toy.
Furthermore, I also compared it to the pictures of quite a few of the examples of mr. Cullen's autograph on Google pictures
, and it matches on a whole lot of points. I think the points you mention could be explained by the texture of the plastic, which offers much less resistance to a signature and which might cause the initial long uprights of the 'U', after which he seems to get more careful with his strokes. It's a strange thing to say, but it seems not 'perfect' enough to be forged.
However, as I stated before, it does give me the sense this was signed quite a long time ago, instead of at a recent convention. Like you mention, there seems to be a correction in the 'R' of PRIME, which does seem to indicate a lack of familiarity. And just the plain fact that mr. Cullen felt a need to write the character name next to his autograph. Last of all, this was never a selling point of the auction! That leads me to believe the item passed into a family who never gave much importance to the (value of)
the signature, and still just saw it as a toy to play with, instead of displaying it.
Anyhow, all of this is pure guessing and theorizing. The seller has also given me positive feedback, so I'll get about sending him a message to ask if he possibly knows more about the history of this item. And perhaps I'll also shoot of a message to mr. Cullen's agency, to ask their opinion.
Now this is interesting: while looking at the seller's profile to contact him, I noticed (by way of the feedback) this item
, sold by the same seller as the one that I got my lot from
! Another signed Optimus Prime, this time OVER the trailer sticker! Signature is very much the same style, although defintely not a stamp
Description by seller is as follows:
Thats right signed by the great Peter Cullen who did the voice of Optimus Prime in the 80's and the recent films. I was at an estate sale when i can across some boxes of toys. when i opened the box there were a handful of vintage transformers, Optimus Primes is one of them, he comes 100% complete and is in good condition. He has some play wear and chrome wear but not broken at all. I see a signature and after research it proves to be Peter Cullen. I don't know when it was signed as i wasn't the one who got it signed.
Once again, the toy seems to have been played with AFTER it was signed (sticker is damaged)
and I have to say, the signature on mine looks a lot nicer, due to being on the bare plastic.