Is This Serial Number Unusual Enough?

Absolutely not.

Technically yes as it has two triples (4s and 5s) but its not something that most are after, especially when they are not together like 44415557 its less obvious. Or 44455577 or 444455777. There are lots of different fancy serial numbers that are out there like those mentioned above, some are truly hard to find and therefore have a nice premium and those who are collectors, serious or not go after them. There is also alot of very minor fancy serials numbers and interesting (such as as a date, birthday) that might appeal to a much smaller group and not at all to others. These you have to check places like ebay and make sure to look at sold listings as anyone can list something at any price but may never sell to see if there is anyone who might be out there interested. In some cases people buy things on impulse but really shouldnt as it might not have real value otherwise if they tried to resell it to a dealer or collector.

Just checked it on the coolness index. It's 91% cool.