Hey @anandd4,
Interesting issue 
I had to try some things with the Go date parser to understand it.
The thing here is that the Go date parser used by Beats uses numbers to identify what is what in the layout. Months are identified by the number 1. In string representation it is Jan, but in numeric representation it is 01. In your layout you are using 01 to parse the timezone, that is 01 in your test date. 01 interpreted as a month is January, what explains the date you see. The rest of the timezone (00) is ignored because zero has no meaning in these layouts. Actually, if you look at the parsed date, the timezone is also incorrect. Timezones are parsed with the number 7, or MST in the string representation.
Summarizing, you need to use -0700 to parse the timezone, so your layout needs to be 02/Jan/2006:15:04:05 -0700.
Find here an example using Go directly: https://play.golang.org/p/iNGqOQpCjhP
And you can read more about these layouts here: https://golang.org/pkg/time/#pkg-constants