shouldn't do, any apps purchased through the play store should just show up as purchased on any android device you have your account linked to. So if you wipe your 7 when you sign into your playstore using the same account they should just be there to download
Sign into the same play store account which you purchased the apps on originally, if it's asking you to purchase again, try restarting the device. It happened to me once but restarting fixed it.
thanks, gave it a restart and all apps showed in play store.