I don't understand how it matched the time part as the first part of the match requires alphabetic characters followed by a space followed by digits and there is nothing in the time part that could match that sequence. The only thing I can think of is that the program is actually doing a "replace" operation and is removing the date part and only leaving the time on the output line.
Also, I'm a bit confused by you comment about "just as long as it grabs the line with the date". Are you expecting the pattern to find the date from the complete text of the email or are you able to guide the regex to only the line and want it to extract the the date part? I did say that the pattern assumes you are only scanning the line with the date on it.
Assuming that you can sort out the find vs replace situation, if you are searching for a date within the entire text of an email, then I would use something like:
[A-Za-z]+, [A-Za-z]+ [0-9]+, [0-9]+
which also includes the day of the week to make it a bit more specific.The pattern I presented before would also match "Fred 56, 32" etc.
In fact, if you can either accept the full date/time string or there is a way of extracting the match groups fom the overall match, then something like:
[A-Za-z]+, [A-Za-z]+ [0-9]+, [0-9]+ [0-9]{2}:[0-9]{2}[AP]M
would match the entire string. While it would also match "Meters, Distance 23, 6594 43:23AMICABLE" this would seem a much less likely false positive.
Susan