You could try restoring the pacer if you like and want to keep his colour, dark bay isn't tooo tricky to match, and although it might not look perfect, he'd be fine for shelf display.
My tips would be give him a thorough wash in a bucket of warm soapy water to get rid of any residue from whatever they've used on him, then use thinly applied acrylic paint to the patches.
The first few layers can be a roughly right dark brown, then pay more attention to the colour-matching of shading on the final layer or two, blending it out gradually onto the original colour at the edges.
As I said on someone else's topic not long ago, any difference in paint shininess can be polished up with a bit of fleece (I mean something you've got anyway, like a blanket, jacket sleeve, dressing gown etc. rather than the actual sheep kind of fleece
)
If it doesn't go well or you struggle to match the paint, you could always just paint him all over anyway; he'll look better than he does now, and he isn't a rare or valuable or sought-after model so it wouldn't be a shame to change him.
For the missing ear tip, I use Milliput but it depends on what's readily available in your country, I never hear anyone outside the UK talking about Milliput in the model horse hobby so I suspect that means it's either not sold elsewhere, or you all have much better/cheaper/easier-to-find alternatives
As long as it's something which sets hard on it's own rather than by baking, some you combine two different materials from the same box and when mixed they set hard, others dry by exposure to air though these are less likely to bond to the model and stay in place.
Once set, you'll have to paint the ear to match the rest, but it looks quite a simple colour to match - an off-white base coat, then a smudge or dry-brush application of colour-matched gingery brown.