Thanks for purchase advice- some more please?

I came across a beautiful 1982 300td on the net. 250k. Almost all highway miles since purchased at 70k (2nd owner). Used to travel within 3 state area by software consulting business run by husband and wife. Husband passed away and wife is selling now a year later.
She states that she knows 1st owner. He had $$$$ and custom- ordered this wagon in "indigo red" with a buff leather interior. Swears it's real leather as they have had 2 other MB with tex and she can tell the difference. Indigo red, she states, is an iridescent salmon-y color which has great depth and changes colors in the light. Mint interior and exterior except for small bubbles of rust near rear quarter panel. States she has most receipts including but not limited to: factory rebuilt transmission, cruise module, motor mounts, shocks and struts. States husband had oil changed religiously every 2k. CD player but has original in-dash cassette if I want it.
Down side: antenna broken off, husband bought new antenna and kit before he passed away and will include with the car. Passenger window won't go down.
She is including also a bunch of oil and fuel filters he had purchased.
Was it possible to custom order? She states that in 1982 the 300td had the 500 series suspension which results in a superior ride.
She wants $5750- I told her nicely that was quite high but we didn't talk turkey, really, as she's going to shoot me some more pics and see if she can get full receipts from the dealership.
Any input?