Creating Galaxy S5 emulator

Instructions for Samsung Emulators for Android Studio and Eclipse are located here:

Using Samsung Emulator Skins for Android Application Development https://developer.samsung.com/galaxy/emulator-skin/guide

The skins can be downloaded here:
http://developer.samsung.com/technical-doc/list.do?pi=1&ps=50&pb=Y&ct=CT350000&sc=

I think it isn't necessary to update your S4 emulator since the changes are minor. However, if it is for testing applications or develop purposes I would recommend update it, because than the minor updates aren't minor anymore, the smallest change may result into a crashing application or a complete different behaviour. Hope this helps.