How can I find out if the private key I exported from Multibit a while back is password protected? Can I tell just by looking at the file contents?
Yes.
No password:
# KEEP YOUR PRIVATE KEYS SAFE !
# Anyone who can read this file can spend your bitcoin.
#
# Format:
# <Base58 encoded private key>[<whitespace>[<key createdAt>]]
#
# The Base58 encoded private keys are the same format as
# produced by the Satoshi client/ sipa dumpprivkey utility.
#
# Key createdAt is in UTC format as specified by ISO 8601
# e.g: 2011-12-31T16:42:00Z . The century, 'T' and 'Z' are mandatory
#
KxYTFo2PaMwSwiUpheCYR6CRyNnVjvYMtZBr4bBKbjEJbJN1m84F 2015-04-27T20:16:35Z
# End of private keys
Password:
U2FsdGVkX180046QdJ+S+Ox/t6xIWud9NI66yrAc07ogteXBAdsUsm43BeYaHsW3ApxEwEjhIp/D
dtU24kNDcT95jqCdMj0eHfCIoADqgTXp91axjBA0NOLfGGSvbYv+
