It depends what will be your data package for the Plan 499 and the model of the device (in case you are getting one). If the device is LTE capable then they Globe will provide you an LTE sim. As for the prepaid number to be used on your postpaid plan, apparently it is not applicable. You will be provided a postpaid sim with a new number. However, you can request for a replacement prepaid sim with the same number and LTE capable by just visiting any Globe Store within your area.
got my plan 499 yesterday.
lenovo a536 for my son and the LTE sim i'm using now in my note 3
unfortunately, our area is not covered by LTE