They are two reeds instruments so do not sound "cajun". However, they are excellent instruments in their own right and are perfectly suitable as a beginner instrument.
I started out on such an instrument (Hohner 1140 / 1040) and I'm glad I chose this one vs. a Hohner Ariette. A 1040 / 1140 is a fine instrument with good sound and excellent response. Really helps when one starts out and struggles. They can be had for cheap too.
Also, a pressed wood Hohner is pre WW2 so make sure it's all refurbished and tuned up.
Pressed wood Hohners were made into the 50s with Prewar NOS parts. Not uncommon.
Decent instruments.. but as said, be wary of age and brittle wax and corroded reeds.
I suggest you go to the melodeon.net discussion group where there is a greater appreciation of all models and styles of diatonic accordeons.
I am certain you will get useful advise there.
If you are intent on playing "Cajun" music around Cajuns.. bringing a Hohner 2 reed 1040 would be like bringing anything other than a Martin D-18 or D-28 to a bluegrass jam. It's as much about image as it is th4e music.. perhaps moreso.
Go tot he Button Box web site go to other merchandise, got to books..
Gte a copy of Roger Watson's
" Handbook for Melodeon " . $14.95..
A simple but good introduction to the diatonic accordeons and specifically Hohner. Complete with descriptions of the various models and some tips and tunes to get you going.
The 1040 (1 row 4 bass buttons) is a fine instrument if you can get one for cheap (say, 200$ or less, a bit more if fully refurbished and sold by a pro). An ideal starter box.
If you want a really versatile instrument, you may want to look at the equivalent two rows (Hohner 2915 or Erica).