You’re mixing up the model designation with the application code.  An “A” suffix added to the basic model number, #1 or #2, meant it was equipped with the (useless) locking lever.

So this sight is merely a correct #1 coded DA.  If you’re going to mount it on a rifle, you’re paying extra for a box you don’t need, & may wind up somewhere down the road getting separated from that sight anyway.  Unless, like me, you NEVER loose or misplace anything!  (I wish!)

Chuck said
I disagree about the box not being important.  Keep it safe and add a note which gun it should be kept with and someone 100 years from now will thank you or maybe next week.  

What I’m sure AG meant was that it’s not important to someone intending to mount it on a gun, rather than keep it unused in the box as sight collectors do.  (I remember being rather amazed when a dealer told me long ago that there are those who buy sights, esp. in boxes, merely to keep like a stamp or coin collection…whereas I’ve never bought any sight I didn’t have a place for on some gun I already owned.)

The problem with “keeping it safe,” aside from the nuisance value of doing so, is that “shat happens,” unforeseen & unpredictable.  It’s what has happened to the empty sight boxes that often show up on ebay, as well as many gun parts, like the receiver sight slides that have to be removed when a scope is mounted; for sure, their owners never intended to separate them permanently from the sight base, but “shat happens.”

The person who will thank him 100 years from now (if he passes on it) will be a sight collector…if any are left by that time.

Chuck said 
Keep it safe and add a note which gun it should be kept with and someone 100 years from now will thank you or maybe next week.  

Here’s an example of what I’m talking about when I say, despite the best intentions, “shat happens”:

https://www.ebay.com/itm/233342405235?_trksid=p11021.c100851.m5053&_trkparms=aid%3D1110001%26algo%3DSPLICE.SIM%26ao%3D1%26asc%3D20170803121420%26meid%3D46143e0d1c8142d893037b1dd7394901%26pid%3D100851%26rk%3D1%26rkt%3D4%26b%3D1%26sd%3D383154987709%26itm%3D233342405235%26pmt%3D0%26noa%3D1%26pg%3D11021&ul_noapp=true

Somebody, obviously, removed the sight from the box & mounted it on a rifle, but deliberately “saved” the box.  That somebody didn’t simply throw the box away (the fate of the vast majority of ALL packaging), or it wouldn’t still be around; no, he thoughtfully “saved” the box, and yet, where is the sight it once contained? 

If they’re both DAs, then one of the stems & sleeves has been replaced–the shorter one.  I presume the stem is shorter because its length should be proportional to the length of the adjustment sleeve.  Wouldn’t bother me that much, but the DA being the most common variation of these sights, finding a “correct” one, & reselling the odd-ball one, should be easy as falling off a log.

By the way, whoever called this #1 the “first variation (Stroebel, I surmise) didn’t know what he was talking about.