You would be best to get a screen protector and here is why.
It is VERY hard to scratch that glass on the IPhone so it's not really that you are protecting it from. Having a screen protector will help if you drop the IPhone. It reinforces the screen and keeps it from cracking.
I'm a Zagg fan and went with the no smudge/no glare version and it's awesome.
Until another retailer has them in stock you will have to purchase another cable from the Apple store or online. Keep checking retailers...they will eventually get them in if they don't have them already.
I would suggest a screen protector regardless of what device you have...unless you get a case that has a built in screen protector...and sometimes, I might still opt for my own screen protector. I've ever used Zagg but I have heard great things about them. I used the PureTek screen shield on my 4s (I ended up having to take it off when I switched to a Otterbox Reflex case because the case messed it up during installation of the case) and it was great....when applied correctly (same as some have mentioned with the Zagg). You can get cheaper ones...the VZW store sells a 3 pack for $14.99 that works fine. It's just up to you.