Is this a CUD on my gold coin ?

I recently purchased this 1805 $5 gold coin in a NGC DETAILS holder (Mount Removed) and noticed a blob on top of the "U" on the word "UNITED" on the reverse. when I purchased the coin I assumed it was some kind of damage from being in a mount. but did some research and I found some auctions that have ended with coins very similar to mine. they describe the blob as a Cud.
(links below) I know there is a Die crack running through the 0 on the date. there is other damage on the coin but wanted to know if the blob is a Cud.

So I guess my question is, is this a Cud ? and if so is that considered an error ?

auction links
#mce_temp_url#

#mce_temp_url#

 

Log in or Sign up to hide this ad.

It does appear to be a CUD in my opinion, and is therefore an error.
Beautiful coin, by the way.

 

thank you. both auctions describe the variety as Breen-6445 BD-1 . so I assume thats what mine is.

 

Awesome cud!!!

 

That is a cud. Note the corresponding weakness of the denticals on the obv to the right of star 8.

 

I think it's a cud beautiful coin by the way I think I thought seriously about pursuing it myself if its the same one I'm thinking of

 

thanks