Have to agree with Big-Block, I listen to a weekly podcast of flight stuff (I know, not cars), and a guy, Lucien Miller (?), a very wide distributor of Scorpion Motors, and the owner of
http://www.innov8tivedesigns.com
He ALWAYS recommends cutting the pre-tinned part off, and re-doing it, because you really don't know what solder CC used.
It could be a high, or low temp solder, and it would be better off to use the same constant solder all around, then having your own, let's say low temp solder mixed with high temp solder, the bond between the two wouldn't be as solid, as it would be with a constant low temp solder..
Temp is just a variable, could be anything, really.