I would....
That is a lens Omega sold as a kit lens. You can still buy a brand new one for $70.
To give you some type of comparison, I have an Omega branded 75mm lens. Comparing this lens to 80mm Nikkor or 50mm Nikkor, there is a world of difference even at the center. Enlarged to 8x10 size, to my naked eyes, there are some difference - although not great big difference. Omega looks "a tad" soft. If I look at it with grain scope, the difference becomes obvious. Using Omega, the film grain never sharply focuses. With Nikkor, of course, it's sharp.
It is possible my Omega lens is defective but like you said - with today's give-away prices of good Nikkor, why wait....