Can I safely update to ios7 without the original SIM card?

Guys i have an iphone 4s running ios 6.1.3 and I'm wondering if I can update it to ios7 without the original sim from Verizon, right now I'm just using it like iPod,.by the way I'm from the Philippines and the phone was just given to me.

No strings attached. Do it.

Should be OK. The OS is held in the phone memory, not the SIM.

On Verizon the 4s doesn't require the sim to be programmed. It uses CDMA so the sim is only for international travel outside the us on a gsm network. You don't even need a sim inside the device. So update to your hearts content. No worries, friend.