help identify a washburn 5 string

i recently bought a washburn 5 string banjo for 300 dollars from my girlfriends dad who paid 400 for it at a local music store around 7 or 8 years ago. it was used when he bought it and had some fret wear but in really good condition. i am trying to figure out the age and value of it. not interested in selling it i would just like to know a little about it. it came with a black hardshell case kinda like chipboard but nicer with silver piping around the edges and no brand name or logo. the banjo itself has the washburn name in the headstock with what looks like the gibson custom shop logo beneath it. it appears to be factory tho. it has a set of gold plated planet five star tuners that are not factory and a pearloid truss rod cover that has a cursive C and says custom made. it has bowtie inlays. 22 frets. 24 brackets. it is an archtop head. it has a nice gold plated tail piece and a gold plated gibson armrest. im not sure the wood type it appears to be walnut or mahogony. on the back of the resonator it has a gold eagle inlay with 3 arrows in one of the talons and an olive branch in the other. it is a great sounding banjo. i am friends with a top notch banjo player that is very knowledgable and has a great banjo collection including some 1920s gibsons and other vintage gibsons. he says he has never seen a gibson armrest like the one on mine but it plainly says gibson in cursive and has a flower design. he says the tone ring appears to be custom handmade by a guy that used to live around here but he is dead now and i cant remember his name. the tone ring is brass and the hardware on the resonator and brackets are all nickel. i think that someone made a frankenstien custom and just used whatever suited them but i would like to get as much info on the washburn part as i can. i think it may be 70s era. i know this is a lot of info and i will try to post pics asap. also i have looked in the resonator and all over the banjo and cant find a label or serial number anywhere!! any info would be greatly appreciated1 thanks in advance!