Welcome Thursty, and you are in the right place for information.
My addition to the discussion is to question what you intend to do with it - will it be put to use or are you looking to sell? Desire and availability in the sellers market are what dictates price, so what are they going for in your area? Here in Sydney, base price is around $300 with refurbished or decent looking machines start from about double that.
The biggest 'cost' of any resurrection is your time. Add to that the delays you'll contend with as you can only do so much in the current cold season. For example, you can't paint in this weather unless you have a proper setup. Do you have someone in mind to sharpen the reel and bedknife - that'll add cash to the costs column and to back up a step - can you blast the reel in the first place to "do it right". You won't know what rust issues you are contending with until everything has been removed - and that will also let you know the condition of your rails.
The model 45058 is a more common mower, so in my opinion you will not get premium resale value. From the images, the unit does look to be in good cosmetic shape - the catcher is especially nice, as are the handlebars. I do note the colour of the reel - others (BB) may know the answer already but can you say it hasn't been refurbished before?
Cheers,
TC.
