I'm not an expert, but I thought the A1200 didn't come by default with a clock battery, and if it had one, it wasn't the leaky kind. If you open it up and you have a barrel shaped battery, then yes it'll potentially leak. If you have a coin, then you are golden.
http://amigakit.leamancomputing.com/catalog/product_info.php?products_id=132 That's the type of battery that will eventually leak.
Even though I had a new one in my system, I decided to go ahead and swap it out with a coin battery.
As per this post,
http://www.lemonamiga.com/forum/viewtopic.php?t=9943"
The 1200 motherboard doesn't have a battery.
If you have an Accelerator/RAM card, it might have a battery on that card."
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