$ cat test.scm
(use-modules
  (guix packages)
  (guix build-system trivial))

(define-public core-pkg
  (package
    (name "core-pkg")
    (version "1.0")
    (replacement core-pkg/fixed)
    (source #f)
    (outputs '("out" "lib"))
    (build-system trivial-build-system)
    (arguments
     `(#:modules ((guix build utils))
       #:builder
       (begin
         (use-modules (guix build utils))
         (let ((outdir (assoc-ref %outputs "out"))
               (libdir (assoc-ref %outputs "lib")))
           (mkdir-p outdir)
           (mkdir-p libdir)
           #t))))
    (synopsis #f)
    (description #f)
    (home-page #f)
    (license #f)))

(define-public core-pkg/fixed
  (package
    (inherit core-pkg)
    (version "1.1")))

(package
  (name "other-pkg")
  (version "4.2")
  (source #f)
  (build-system trivial-build-system)
  (inputs
  `(("core-pkg" ,core-pkg)
    ("core-pkg:lib" ,core-pkg "lib")))
  (arguments
  `(#:modules ((guix build utils))
    #:builder
    (begin
      (use-modules (guix build utils))
      (let ((outdir (assoc-ref %outputs "out")))
        (mkdir-p outdir)
        (with-output-to-file (string-append outdir "/hello")
          (lambda ()
            (display (assoc-ref %build-inputs "core-pkg"))
            (newline)
            (display (assoc-ref %build-inputs "core-pkg:lib"))
            (newline)))
        #t))))
  (synopsis #f)
  (description #f)
  (home-page #f)
  (license #f))
~$ cat `guix build --no-offload -f test.scm`/hello
/gnu/store/pmz07rzm63z02lkyyldsw3srf98h01y2-core-pkg-1.1
/gnu/store/pivsji8qfpln4i4v0f5v5cjmzakmcmvg-core-pkg-1.0-lib

Expected output: the second line contains -core-pkg-1.1-lib.

Regards,
Jakub Kądziołka