emacs 25.3_1 64bit install problem

I am trying to move from ver 24 to 25. I have an  emacs.exe file in my 
version 24.3 bin directory

03/17/2013  14:52         9,055,614 emacs.exe

(working now for almost two years)

and 2 .exe files in my new version 25.3 bin directory:

09/26/2017  16:04        99,358,230 emacs-25.3.exe
09/26/2017  16:04        99,358,230 emacs.exe

These were extracted using 7-zip without any problem but they seem too 
large by a factor of 10.

They are from ftp://ftp.gnu.org/gnu/emacs/windows/ and from the 25.3_1 
zip file. I don't know how to use gpg so I didn't check my download with 
the .sig file.

Also the directory structure is different in this new emacs version. Is 
this what it should look like?:

bin:

09/26/2017  15:59         2,377,025 addpm.exe
09/26/2017  16:04         2,549,713 ctags.exe
09/26/2017  16:04         1,952,311 ebrowse.exe
09/26/2017  16:04        99,358,230 emacs-25.3.exe
09/26/2017  16:04        99,358,230 emacs.exe
09/26/2017  16:04         2,585,253 emacsclient.exe
09/26/2017  16:04         1,965,621 emacsclientw.exe
09/26/2017  16:04         2,528,894 etags.exe
09/26/2017  16:04            77,744 libXpm-noX4.dll
09/26/2017  15:59         1,760,768 runemacs.exe
               10 File(s)    214,513,789 bytes

  \libexec\emacs\25.3\x86_64-w64-mingw32:

09/26/2017  15:59         1,389,805 cmdproxy.exe
09/26/2017  15:59         1,363,317 ddeclient.exe
09/26/2017  16:04           652,767 hexl.exe
09/26/2017  16:04         3,056,390 movemail.exe
09/26/2017  16:04         1,808,582 profile.exe
09/26/2017  16:04            21,154 rcs2log
09/26/2017  16:04         1,800,363 update-game-score.exe
09/26/2017  16:04               381 update-game-score.exe.manifest
                8 File(s)     10,092,759 bytes

and then share and var subdirectories at the same level with a lot of 
deeply buried files.

My question is whether I can expect ver 25.3_1 to work if I just 
incorporate all the new stuff into my old emacs directory structure:

01/24/2017  17:57    <DIR>          bin
03/17/2013  14:52               932 BUGS
03/17/2013  14:52            35,147 COPYING
09/04/2015  15:58    <DIR>          etc
08/01/2015  12:25    <DIR>          gnus
02/01/2015  02:01    <DIR>          gnutls
01/07/2017  17:27    <DIR>          info
12/03/2013  20:21    <DIR>          leim
12/03/2013  20:22    <DIR>          lisp
12/03/2013  20:22    <DIR>          Mail
12/03/2013  20:22    <DIR>          nt
12/03/2013  20:22    <DIR>          nxml
10/07/2015  17:22    <DIR>          org
03/17/2013  14:52             5,753 README
03/17/2013  14:52            13,368 README.W32
09/13/2017  11:31    <DIR>          site-lisp

and can all this stuff in ~
01/06/2014  10:23            31,451 .emacs
02/10/2015  03:41               204 .newsrc
02/10/2015  03:41             1,020 .newsrc.eld
02/10/2015  03:15               913 .newsrc.eld~
02/10/2015  03:15               189 .newsrc~
02/10/2015  02:46            63,180 .nnmail-cache
03/14/2011  22:35             2,116 .notes
03/12/2011  21:32             1,164 .notes~
09/28/2012  11:16               692 .recentf
09/28/2012  08:29               692 .recentf~

remain there unchanged?

Thanks for any help.

Ed

p.s. Why are there two identical emacs.exe files in \bin with different 
names?