It's modernish, but I think that's just a problem on the demand-side; there doesn't seem to be any engineering issues with pulling it off in antiquity that I can think of.
Apart from building a 200 feet tall tower, making a fine copper mesh, and easily melting lead on top of said construction.
It could probably be done, but just barely and at great cost.
You also need the metallurgical know how to figure out how fast the lead cools in order to get the details, such as height, right. Which is trickier.
And you need a reason for somebody to invent it.
I'm in a silly mood and probably boring the rest of you out of your gourds, but:
- What's that mighty tower? Immensely tall, isn't it?
- Yes, sir, it's a little over 200 feet. Twice as tall as the Tower of London!
- Most impressive! A roost for the griffin cavalry, I suppose?
- They use the squatter tower to the left. The one that looks like a huge dovecote. That one's just ten stories, barely half as tall.
- Uh, so it's a mighty wizards tower then? Abr'com the Bloody?
- No, no, nothing like that. It's our shot tower.
- Shot tower?
- Yeah, we make lead ball bearings in it. Hundreds of thousands of them. Except it isn't really ball bearings, being lead and all. Wouldn't work at all.
- Ball bearings?
- Yep, sells like sweet chili sauce on an orc barbecue. Silly adventurers pay solid gold for it. Buy it by the thousands.
- So you built this immense tower just so adventurers can have a go at tripping goblins with low dexterity? Couldn't you find an easier way to make money? Making shovels, perhaps? Or clubs, they go for a silver each.