How do I know if the pop-up window is from Adobe or not?

I sometimes get pop-ups in my browser that tell me I have to update my software. I just got one concerning Flash Player. The link it redirected me to is this one:

https://get3.adobe.com/flashplayer/download/?installer=FP_16_Mac_for_Safari_and_Firefox_-_ NPAPI&os=OSX&browser_type=KHTML&browser_dist=Safari&d=Adobe_Photoshop_Lightroom_for_Macint osh&dualoffer=false&type=au&browser_vers=7

Which I assume is okey. But just to check I went to adobe.com and found the link to install and update Flash player there and the link is then:

http://get.adobe.com/flashplayer/download/?installer=FP_16_Mac_for_Safari_and_Firefox_-_NP API&os=OSX&browser_type=KHTML&browser_dist=Safari&d=Adobe_Photoshop_Lightroom_for_Macintos h&p=ltrosx&dualoffer=false

So no get3 like in the first link. Why the difference, and how can I tell for sure that it is not someone pretending to be Adobe?

Sorry for possibly putting this in the wrong community but I could not find the proper place for this topic, and I had to choose a community to be able to post.