The sale price of $38,495 looks like it is about the average list price that this year and model are listed elsewhere.
$37,995 here: https://www.rvtrader.com/listing/2018-Heartland-SUNDANCE-SD-3250CKSS-5001770392
$39,999 here: https://www.rvtrader.com/listing/2018-Heartland-Sundance-SD-3250-CKSS-5004629156
And $39,999 here: https://www.ronhooversouthhouston.com/New-Inventory-2018-Heartland-Trailer-Sundance-SD-3250-CKSS-Sundance-South-Houston-5274244
So, I think there is probably some room to negotiate a lower price.