Can you use the series 1 1ST GEN screen to series 1 2ND GEN?

"Unfortunately you can't transfer the LCD to the other series one, seems to not be compatible.

Apple watch series 1 and 2 pretty much use the same batteries.

Source: Searched for the batteries and LCDs on eBay."

"Here's the IFIXIT teardown & guides for the different watches:

Orginal Apple WatchSeries 1 & 2Series 3

You'll also find some YouTube teardown and repairs on the IFIXIT channel.

Update (03/30/2018)

@adamusik - Take a look at these two images and tell me if they use the same connector system

Original Apple watch (gen1)

Series 1 (gen2) & 2 as well as Series 3 which uses a different part

These parts are NOT interchangeable!!

The construction of the product doesn't conform to the model ID's

The original watch

38mm: A155342mm: A1554

Unique parts!

Series 1 & 2

38mm: A1802 & A175742mm: A1803 & A1757

Use the same parts!

Series 3 Use some of the same parts as the Series 1&2. The case, S1 board & display assembly are different!

The Apple Watch Edition watches are unique as well as Apple produced them using the guts of the original, those solid gold & ceramic watches Apple gave to the Who's Who celebrities before the roll out of the very first watch and sold for $10K to $20K. And later sold the White ceramic version which used the series 2 guts."

"The first generation apple watch (aka. Series 0) is the exact same thing as the Apple Watch Series 1 (which came out with the Series 2 (Second Generation) but with a small processor upgrade compared to the original Apple Watch).

So an Apple Watch (1st Generation) screen will work on an Apple Watch Series 1.

Now Series 1 and Series 2 Screens are completely different and will not work with each other. And obviously a 38 mm screen won't work on a 42mm screen."

"I just found an article and looks like Series 0 and Series 1 displays and batteries are completely interchangeable.

Update (03/28/2018)

Dan check this (all information from ifixit)

Apple Watch Teardown

step 21

Apple Watch - Series 1

The Apple Watch Series 1 is a revamp of the original Apple Watch, announced September 7, 2016. Most of the parts are the same as the Series 2

Andrew Goldberg's Article

""When we tore open the Series 2, we found a totally redesigned, streamlined, repair-friendly interior.""

""To find out for sure, we warmed our iOpener and unsheathed our opening knife. With the display open, the verdict is … it’s a Series 0 in there.""

""The construction in the new Series 1 exactly matches what we saw in our teardown of the original Apple Watch, right down to that annoying display cable bracket. That’s the exact same 0.78 Wh (205 mAh at 3.8 V) battery, right down to the Apple part number. Just to be sure, we checked compatibility with our original Apple Watch parts stock, and found that Series 0 and Series 1 displays and batteries are completely interchangeable.""

Apple Watch Series 2 Teardown

Step 4

Apple Watch Series 3 Teardown

Step 5"