Welcome to the forums. The subject bicycle should be a 1990 model, as Shimano introduced their 300LX components that year and it was also the last year that Norco marketed their Sekai brand. The Bigfoot was the top model in the Sekai line of 7 ATB models and sold for $400 US. However, despite it's position in the line, it was not a high end model. Norco was marketing Sekai as more of an entry level brand, with the higher end ATB models being offered under their Fiori and Norco brands. From an overall ATB market perspective. it was more of a very low mid-range model. Norco themselves were marketing ATBs up to $1,000 US and 300LX was 6th in Shimano's line of 7 ATB groups. FYI, while CrMo tubing was employed, it was only for the three main tubes. Lower grade hi-ternilse steel was employed in the forks and rear triangle as a cost concession to hit the target price.

While it is only very low mid-range, it should be solid and depedable bicycle, though relatively heavy. You mention drop bars and new wheels but don't say if the intention is to create a road bicycle, gravel bicycle or cyclo-cross bicycle. It could certainly function reasonably well in the last two, with appropriate tyres, though the question is how much to sink into it, as it will always be a compomise and somewhat heavy.