Is a toy a model?

Yes, indeed, a toy can become a model.  I have refinished a crummy looking Star Wars Han Solo blaster to look like a real gun with various shades of metallizer and  weathering. It's a great model now, as far as I am concerned.

Actually a model can be larger than full scale as well. Very common these days in the world of industrial prototypes.

I think it's a great subject- "accurizing" toys. I've done some, in fact am working on one now- the old Texaco North Dakota floor toy.

They present lots of challenges. Most are not designed to be taken apart, in fact usually are engineered to resist it. Also they tend to be made of dissimilar materials that are hard to paint, glue and machine.

Hasbro, Marx and others have made some fairly good looking howitzers in "Joe" or other big scales over the years. They can be had on eBay for pretty cheap. Talking to most redlegs though, they'll be quick to tell you the thousand inaccuracies, but if one were not to take it too seriously...

But it's not a model kit.

Like Timmy said, any scale representation of something larger is a model. By adding/fixing things to your liking, it becomes a customized model. The fun part is making it something that's unique to your own personal vision. That's why most of us in this forum do what we do.

A model is a miniature of somthing larger. To convey the likeness of the original without having to move the real thing or to provide a working idea of what changes can be made to the original.( Arcitects do this with miniature buildings.)  As far as I'm concerned You can call yours a model !  You have improved its toylike features to resemble the real thing in a more realistic and accurate manner. ( Real thing being a reletive term.)  Would love to see some pictures of it.