I'm going to keep him as he is. I have no confidence I'd be able to repaint him to a high enough standard. Leaving him as he is I can also pretend I found him somewhere like the Moldovar market or adrift in space.
Well I had planned to buy some made by a K9 builder but in the end when I went to collect K9 the seller gave me a couple of 3D printed ears to work on plus I found some others on Shapeways so I'm going to give them a go.
The 3D printed ears have come but they look too small and I haven't been able to make anything out of the experimental ears the previous owner gave me.
Update - I've found a model on thingiverse which I've downloaded, uploaded to Shapeways and sized myself. Fortunately they aren't expensive as because of the curve of the ears and not being sure if the width setting accounts for it there's some educated guess work involved.
Here's some comparisons that might prove interesting:
First your ears:
Then my ears:
Then, finally, the real K-9's ears:
I think the size & shape of yours are pretty good.
The only thing I would say about your ears, is the same thing that's wrong with my ears, which is that the wire used to make them is a bit too thick.
Given the variation in K9's ears over the years - and the sorry state they've been in very often - I'd say, 'slightly too thick' isn't too much of a problem.
The only notable difference I see between the 'real' K9 and your two, is that his ears (and the things they stick into) are angled outwards and slightly away from each other. And I only noticed that because of the close-up comparisons.