It's possible, though flipping through iFixit's guides (the 2G, 3G, 3GS, 4, 5, 6, 7, 11, and 14 models), the first time adhesive pull tabs were referenced by them was in the iPhone 3G (the second-generation iPhone). They recommended against using the pull tabs in the 3G and 3GS, though. Unless Apple removed the pull tab at some point and then added it back in soon after (between the model generations I checked), it seems like iPhones have consistently had some form of a pull tab after the original iPhone.

What might have been possible is that the adhesive may have aged to the point where the pull tabs were no longer usable in your iPhone when you repaired it and the battery was essentially glued/adhered to the chassis at that point. Without the pull tabs (which can break when trying to use them), the battery adhesive basically becomes the same as the display adhesive, which also requires heat to remove.